Implemented BMPCProxy and BMPCManager.

- BMPCManager deals with the running BrowserMob Proxy REST API
- BMPCProxy deals with 1 specific Proxy created by the Manager

BMPCProxy can be used by itself if you know Host and Port of the REST API,
but the BMPCManager helps with that.

BMPCManager is an interface and the only implementation for now is
BMPCSimpleManager (that does very little).
A more powerful one will follow soon.
Adding missing license headers.
Adding Gradle instructions to upload Release Artifacts
Initial  Travis CI .yml