docs(0004): BREAKING remove cancellationCondition

what was previously known as Universal mode has been incorporated into the core Interledger Protocol. the Atomic mode is being removed from the core protocol and will be used via extensions to the protocol.
based on #28

0004-ledger-plugin-interface/0004-ledger-plugin-interface.md

@@ -35,7 +35,6 @@ This spec depends on the [ILP spec](../0003-interledger-protocol/).
 | [**error**](#event-error-) | `( ) ⇒` |
 | [**receive**](#event-receive-) | <code>( transfer:[IncomingTransfer](#incomingtransfer) ) ⇒</code> |
 | [**fulfill_execution_condition**](#event-fulfill_execution_condition-) | <code>( transfer:[Transfer](#class-transfer), fulfillment:Buffer ) ⇒</code> |
-| [**fulfill_cancellation_condition**](#event-fulfill_cancellation_condition-) | <code>( transfer:[Transfer](#class-transfer), fulfillment:Buffer ) ⇒</code> |
 | [**reject**](#event-reject-) | <code>( transfer:[OutgoingTransfer](#outgoingtransfer), rejectionReason:Buffer ) ⇒</code> |
 | [**reply**](#event-reply-) | <code>( transfer:[OutgoingTransfer](#outgoingtransfer), replyMessage:Buffer ) ⇒</code> |
 
@@ -191,15 +190,8 @@ p.send({
   amount: '10',
   data: new Buffer('...', 'base64'),
   noteToSelf: {},
-
-  // for UTP/ATP support
   executionCondition: 'cc:0:3:47DEQpj8HBSa-_TImW-5JCeuQeRkm5NMpJWZG3hSuFU:0',
-
-  // for UTP support
-  expiresAt: '2016-05-18T12:00:00.000Z',
-
-  // for ATP support
-  cancellationCondition: 'cc:0:3:47DEQpj8HBSa-_TImW-5JCeuQeRkm5NMpJWZG3hSuFU:0'
+  expiresAt: '2016-05-18T12:00:00.000Z'
 })
 ```
 
@@ -220,7 +212,7 @@ Submit a fulfillment to a ledger. Plugin must be connected, otherwise the promis
 
 Emitted when a transfer is received.
 
-Note that transfers may be conditional, in which case the `receive` event **DOES NOT** indicate that money has been transferred. If users of the plugin wish to check whether they have gotten money, they MUST check whether the transfer has a condition. If transfers have conditions, the final status will only be known when the [fulfill_execution_condition](#event-fulfill_execution_condition-) or [fulfill_cancellation_condition](#event-fulfill_cancellation_condition-) are emitted.
+Note that transfers may be conditional, in which case the `receive` event **DOES NOT** indicate that money has been transferred. If users of the plugin wish to check whether they have gotten money, they MUST check whether the transfer has a condition. If transfers have conditions, the final status will only be known when the [fulfill_execution_condition](#event-fulfill_execution_condition-) is emitted.
 
 The ledger plugin MUST authenticate the source for all incoming transfers, whether they include money or not.
 
@@ -233,15 +225,8 @@ The ledger plugin MUST authenticate the source for all incoming transfers, wheth
   amount: '10',
   data: Buffer(...),
   noteToSelf: {},
-
-  // for UTP/ATP support
   executionCondition: 'cc:0:3:47DEQpj8HBSa-_TImW-5JCeuQeRkm5NMpJWZG3hSuFU:0',
-
-  // for UTP support
-  expiresAt: '2016-05-18T12:00:00.000Z',
-
-  // for ATP support
-  cancellationCondition: 'cc:0:3:47DEQpj8HBSa-_TImW-5JCeuQeRkm5NMpJWZG3hSuFU:0'
+  expiresAt: '2016-05-18T12:00:00.000Z'
 }
 ```
 
@@ -259,18 +244,6 @@ Emitted when a transfer's execution condition has been fulfilled.
 
 If the transfer is an [`OutgoingTransfer`](#outgoingtransfer), connectors will forward the execution condition to the corresponding [`IncomingTransfer`](#incomingtransfer).
 
-#### Event: `fulfill_cancellation_condition`
-<code style="">ledgerPlugin.on('fulfill_cancellation_condition',
-  (
-    **transfer**:[Transfer](#class-transfer),
-    **fulfillment**:Buffer
-  ) ⇒
-)</code>
-
-Emitted when a transfer's cancellation condition has been fulfilled.
-
-If the transfer is an [`IncomingTransfer`](#incomingtransfer), connectors will forward the execution condition to the corresponding [`OutgoingTransfer`](#outgoingtransfer).
-
 #### Event: `reject`
 <code>ledgerPlugin.on('reject',
   (
@@ -308,7 +281,6 @@ fields can be left undefined (but not any other false-y value) if unused.
 | `Buffer` | [data](#data) | Data packet or memo to be sent with the transfer, starts with an ILP header |
 | `Buffer` | [noteToSelf](#notetoself) | Host-provided memo that should be stored with the transfer |
 | `String` | [executionCondition](#executioncondition) | Cryptographic hold condition, used in [UTP](../0006-universal-transport-protocol/)/[ATP](../0007-atomic-transport-protocol/) |
-| `String` | [cancellationCondition](#cancellationcondition) | Cryptographic abort condition, used in [ATP](../0007-atomic-transport-protocol/) |
 | `String` | [expiresAt](#expiresat) | Expiry time of the cryptographic hold, used in [UTP](../0006-universal-transport-protocol/) |
 | `Object` | [custom](#custom) | Object containing ledger plugin specific options |
 
@@ -375,15 +347,6 @@ Ledger plugins that do not support holds MUST throw an `HoldsNotSupportedError`
 
 Ledger plugins that do support holds, but do not support the given condition type or bitmask MUST throw a  `ExecutionConditionNotSupportedError`.
 
-#### cancellationCondition
-<code>**cancellationCondition**:String</code>
-
-A [cryptographic condition](../0002-crypto-conditions/) used for implementing holds. If this condition is met and the transfer is on hold, the ledger MUST cancel the transfer and return the funds to the sender.
-
-Ledger plugins that do not support holds or do not support cancellation MUST throw a `CancellationNotSupportedError` if this parameter is provided.
-
-Ledger plugins that do support cancellation, but do not support the given condition type or bitmask MUST throw a `CancellationConditionNotSupportedError`.
-
 #### expiresAt
 <code>**expiresAt**:String</code>