Simplify version tracking, and get some edge cases working. Use the version tracking system instead of shared preferences based approach. Fix broken tests. Move some test data into separate files.
Reformat Apptentive.java
Add time_since_install, which replaces days_since_upgrade and days_since_install. Also add three sub filters: total, version, build. Add or modify tests for these.
Merge branch 'engagement_and_push' of https://github.com/skykelsey/apptentive-android into engagement_and_push