Update the Travis-CI build for the community edition

[emxsys]

Establish the Travis-CI build for the community edition.

• Publish API docs to https://worldwind.earth/WorldWindAndroid
• Publish SNAPSHOT artifacts to oss.jfrog.org
• Publish release artifacts to Bintray/JCenter

[emxsys]

Work is in progress.

[EMaksymenko]

@emxsys Would you help me to finish this to be able to correctly release my latest changes?

I have changed artifact name from gov.nasa.worldwind.andoid:worldwind to earth.worldwind:worldwind-android to bi similar with Java artifact earth.worldwind:worldwind.