Move platform specific code to portable project.

Switch to SQLitePCL.
Setup integration test app.
Add test framework.
Http per request.
Fix broken test.
Fix test project.
Fix count, id generation and missing version on insert.
SQLite fixes for conversion and more.
Do not cancel.
Downgrade Json.NET.
Fix column derivation if initial value is null.
DownloadChanges should return its result.
Functional changes to the testframework to support initialize and cleanup.
Add test from storage.
Update packages.
Integration test app.
Fix bug in tests.
Fix delete needs version.
Fix lowercase bugs.
Fix responsehelper null handling.