Added InvalidAlgorithmError class, and reorganised to follow psr-4 layout

README.md

@@ -1,9 +1,71 @@
 # php-http-signature
 
-HTTP Signature Authentication library for PHP that has client and
-server components for Joyent's HTTP Signature Scheme, as specified
-at http://tools.ietf.org/html/draft-cavage-http-signatures-00 and
-implemented at https://github.com/joyent/node-http-signature.
+Note: I've updated the source file and directory structure to follow psr-4 layout for autoloading as composer package.
+
+For example in composer.json, you can add the following to autoload the class...
+
+```
+"repositories": {
+    "http-signer": {
+      "type": "package",
+      "package": {
+        "name": "gwynne/http-signer",
+        "version": "1.0.0",
+        "source": {
+          "url": "https://github.com/58bits/php-http-signature",
+          "type": "git",
+          "reference": "7abfde5fc7ad29b62446fb59c967458f48227220"
+        }
+      }
+    }
+  },
+
+"autoload": {
+    "psr-4": {
+      "Gwynne\\": "vendor/gwynne/http-signer/src/"
+    }
+  }
+```
+
+`composer install` would then automatically clone the repository into the following vendor directory...
+
+```
+── composer.json
+├── composer.lock
+└── vendor
+    ├── autoload.php
+    ├── composer
+    └── gwynne
+        └── http-signer
+            ├── LICENSE
+            ├── README.md
+            └── src
+                └── HTTPSignature.php
+```
+
+Using the signature class then becomes...
+
+```
+require 'vendor/autoload.php'; // Loads all vendor related 'requires'.
+
+$date = gmdate(DATE_RFC1123);
+$headers = array('date' => $date);
+
+Gwynne\HTTPSignature::sign($headers, array(
+    'key' => '46653e78ce9df4f2d9ae93gft5f5c281',
+    'keyId' => '18KF2FGK6807ZQA9FGT4',
+    'algorithm' => 'hmac-sha1'
+));
+```
+
+(although this class should really contain instance members and be 'new'd' up when used.")
+
+I've submitted a pull request to the author.
+
+# Original README
+
+
+HTTP Signature Authentication library for PHP that has client and server components for Joyent's HTTP Signature Scheme, as specified at http://tools.ietf.org/html/draft-cavage-http-signatures-00 and implemented at https://github.com/joyent/node-http-signature.  
 
 ## Usage