Added gradle files and restructured for AndroidStudio

[brennv]

Hello and thank you for all the great code examples -- I'd definitely like to contribute. I added all the gradle files and restructured the schema for AndroidStudio. I then tested the import-ability of AndroidPlot with AndroidStudio. If you'd like to see this done differently, please let me know and I'll start working through the other examples. All the best, Brennan

[IanDarwin]

Thanks, and sorry for letting it languish over the summer. I'd really prefer to keep compatibility with Eclipse (since their AndMore project is maintaining the ADT code now). One way that should work would be to make this entire repo be one big A/S project, with each current folder becoming a Gradle "module" (initially just calling the Ant or Maven build) with the present names instead of "app" which it normally uses. Then it could be built either individually or as a group. A side benefit is that no (or few) files need to be moved around. Do you think this would work?

Again, thanks for taking this on!