Fixed issue #8 by porting changes from Android

- Ported JsonCollator changes from Android (couchbase/couchbase-lite-android#290)
- Added 2 Native methods for testing JsonCollator and RevCollator from Java code.
Made codes compatible with MSVC and Updated build.gradle

- Made codes compatible with MSVC (issue #1)
- Updated build.gradle to add maven support (issue #2)
- Fixed platforms in build.gradle
Merge remote-tracking branch 'upstream/master'

Conflicts:
	build.gradle
	src/main/java/com/couchbase/lite/Native.java