Bug#826870: [Android-tools-devel] Bug#826870: android-sdk: Gradle missing

[Hans-Christoph Steiner]

Since gradle is not absolutely required, but by far the most popular way
to build Android apps these days, I think at the very least we should
put gradle in Recommends:  I guess it makes sense to keep it out of
Depends: since some people might be only building with ant, maven, etc