Try new android build environment on Travis CI

See https://github.com/travis-ci/travis-ci/issues/1395
Merge branch 'master' into test_travis

Conflicts:
	.travis.yml
deploy android-20
don't use sdk-deployer
Revert "don't use sdk-deployer", it's still needed for maven projects

This reverts commit c8a65f326500e50d367b919abd076f325a1e7da8.
there is no seperate buildstep
build with gradle
build against both openjdk7 and oraclejdk8
run test with gradle, no need to build first
Revert "build against both openjdk7 and oraclejdk8", unit tests with
gradle fail with oraclejdk8

This reverts commit 80c36d098e608ad84f8b9dd8f15766ccd8d048e0.