Updated Travis configuration
Updated AndroidPublisher library to rev8. Use StringUtils.isNotEmpty instead of !StringUtils.isEmpty.
Merge pull request #10 from Triple-T/travis

Updated Travis configuration
Merge pull request #11 from Triple-T/cleanup

Use StringUtils.isNotEmpty instead of !StringUtils.isEmpty
Refactored PlayPublisherPlugin:
 * Use variant.zipAlign instead of try-catch.
 * Refactored creation of inputs for PlayResourcesTask.