Remove prefixes using static import
Merge pull request #347 from amatellanes/master

Remove prefixes using static import
Switch conditional to OR.
Merge pull request #350 from square/jw/or

Switch conditional to OR.
Custom transformations should throw on main thread.
Merge pull request #355 from square/dimitris/throw-to-main

Custom transformations should throw on main thread.
Update readme with proguard instructions.
Merge pull request #356 from square/dimitris/update-readme

Update readme with proguard instructions.
Add Travis CI build.
Merge pull request #357 from square/jw/travis

Add Travis CI build.
Merge branch 'master' into disk-cache