Update the scanBlocks request and integrate with the data that it generates inside dataDb

App is functional and displays transactions

…nit5 setup

streaming is working and tests are functional

On the rust side, we now have access to the init DB commands. On the Go side we have time available for blocks

…tors

The synchronizer now primarily collaborates with a downloader, processor and repository; each with a more focused set of responsibilities.
The downloader streams blocks into a channel, the processor saves blocks from that channel and scans for transactions, the repository
exposes transaction change events.

When a transaction is sent it transitions through a lifecycle, beginning with creating the raw transaction and ending with it being mined and added to the blockchain

Send is now functional and shows up in active transactions.
This involved:
- reducing the exposure of the seed
- consistently using Ints for blockheight everywhere to match zcash
- adding the use of spending keys
- adding account initialization on startup
- using accounts but defaulting to account 0
- internalizing birthday so we no longer need a reference outside of the library
- enabling cancellation during send
- cleanup active transaction manager

After experiencing several issues that make it more difficult to test send behavior, including the amount of time required to wait for blocks to get mined when testnet is slow,
it became obvious that it was time to investigate mocking. Most of the behavior in the SDK is driven by channels so the mock only has to focus on putting useful data in the
expected channels at the right time. One tradeoff here was the need to make all the synchronizer properties private, that way any implementation can achieve compatability
without necessasily leveraging the same combinations of building blocks. This tradeoff felt acceptable given that these dependencies can be injected and available as singletons,
if needed. This also had a side effect of elevating several channels into the Synchronizer interface, rather than reaching into the synchronizer to directly access those dependencies.
Another benefit is that it's now easier to see what matters most to the app, particularly which channels are essential.

Working with bigdecimals anytime we need to multiply or divide values because it was causing issues when repeatedly toggling currency on the send screen. Coupled this with lots of improvements on the app side to do less processing while changing currencies

It is not really practical to try and use JUnit 5 for Android Instrumentation tests at this time. See documentation in build.gradle for details.

Never start downloading blocks prior to sapling activation height, only allow firstrun when dataDb is empty and also add birthday support. Also added corrections to isFirstRun logic.

This allows the app to show an error dialog rather than crashing silently

This commit will get iteratively polished until the PR is ready
- Addresses PR feedback #16 (comment)

Remove unused functionality and disable modification to tables that should only be written by librustzcash