upgrade android plugin and gradle version
add evaluationDependsOn(:app) in robolectric-tests:build.gradle
Revert "add evaluationDependsOn(:app) in robolectric-tests:build.gradle"

This reverts commit 69b76dd370456ff1bb62287cacdd0829958b9e31.
fixes #4
only depend on the debug variant of the android module
Merge pull request #5 from friedger/master

Upgrade tools