Renaming DrawableWithAlpha#setAlpha(float) to #setAlphaCompat(float), and #getAlpha():float to #getAlphaCompat():float, to fix build errors related to invalid method overrides.
Updating target SDK version to API level 19, and updating build tools version to the latest version (20.0.0).
Adding a keystore that can be used to sign untrusted builds in release mode.