Update Gradle configs
Add task to upload to Sonatype

* Adds following tasks: jarRelease, jarDebug, uploadArchives
Add Travis-CI
Prepare for next development iteration
Merge pull request #24 from BoltsFramework/grantland.travis

Add Travis-CI
Merge pull request #22 from BoltsFramework/grantland.sonatype

Add task to upload to Sonatype/Maven Central
Fix Travis-CI

* Travis-CI doesn't have a configured signatory, so don't sign for SNAPSHOTS
Merge pull request #25 from BoltsFramework/grantland.signing

Fix Travis-CI + Signing