[Proposal] Use JCenter and Maven Central instead of the homemade repository.

[shrhdk]

This project is using the homemade maven repository. However the public maven repository such as a JCenter and Maven Central are more useful for users. And that is a generic way. Including generated artifacts in the source code repository is not a good idea.

Javadoc.io automatically web-hosts Javadoc JARs in Maven Central. This service is useful for both library developers and users.

I think that the following step is recommended.

1. Create a new repository in Bintray.
2. Upload artifacts to repository created in Bintray.
3. Sync the artifacts to JCenter from Bintray. (It can complete with almost one-click.)
4. Sync the artifacts to Maven Central from Bintray.