Update gradle, android gradle plugin, and build tools to the latest versions
Remove unneeded gradle files as we use the ActionBarSherlock AAR
Merge pull request #612 from willlunniss/update-build-tools

Update build tools
Show application description and change log as html

Play Store description and change low support a subset of html tags: http://stackoverflow.com/a/18746972/239438
Merge pull request #615 from Giorgi/patch-1

Show application description and change log as html