Upgrade android plugin, gradle wrapper, and tools

[joebowbeer]

Keeping up with changes in Android tools:

• android gradle plugin 2.1.2
• gradle wrapper 2.13
• build tools 23.0.3
• android support 23.4.0

Note: Additional dependency commands were added to CircleCI to accommodate the build tools and android support upgrades above.

Bumped version to 1.0.2-SNAPSHOT Removed extraneous gradle wrapper task configuration.