Welcome back, gradle. Thanks to gradle tools 0.5.4.
[ci skip]
Travis now build HE with gradle
Update link on idea/studio article in wiki
Update IDEA/Studio project files [ci skip]
Add AppSales to featured list

[ci skip]
Fix #554
Update to support library 18.0.1 and remove some *.iml files
Update ABS reference [ci skip]
Add ABS as dependency to library (fix #559)
Support of options menu in nested fragments (updated ABS)
Update support library for maven build [ci skip]