updated to latest version
fixed #27 - Only 12 hour format time is stored in shared preferences.
Merge pull request #39 from mars3142/feature/issue_27_fix

fixed #27 - Only 12 hour format time is stored in shared preferences.
Merge pull request #38 from mars3142/feature/latest_build_tools

updated to latest build version
remove proguard file, it's not used
update play image