Travis CI fix

[CarlosACepeda]

Fixing the CI build in Travis CI by doing the following:

using the same build tools as the Gradle file at app level. chaging the jdk from oraclejdk7 to openjdk8 (most modern) Fixing a flag that's no longer available when starting the emulator -no-audio flag

So far it's still failing with: junit.framework.AssertionFailedError: Failed to write to the file. So I'm trying to find a fix for this