Travis Snapshots Configuration

[Ru13en]

@pvilaca for some reason i cannot release SNAPSHOT versions of Core or other packages of biotexmining.
Check:
https://travis-ci.org/biotextmining/core/builds/615593272?utm_source=github_status&utm_medium=notification

It compiles, makes a release on github, but doesn't deploy to Nexus.
Since is Travis making the deployment, i don't know if you validated the deployment of SNAPSHOT versions.