Renamed Java packages to match our contiki-os.org domain. Note that this commit does not affect external dependencies
like /tools/mspsim.

This is a very simple modification that affects a very large number of files in Contiki: Cooja,
/platform/cooja, Collect-view, Coffe-manager, and Cooja simulation files (.csc).

I've gone through Contiki to update all references I could find. Nevertheless, this commit will likely
break external dependencies, like saved Cooja simulation files.
Cooja backwards compatibility with simulation files that uses non-Contiki Java package names