Commit for the PR

The pull request targets:

	1) Introduces Gradle support
	2) Updates maven support (even thou the apk generated is not
stable)
	3) Updates the setup_env.* scripts to support different building
tools
	4) Removes non UTF-8 characters
	5) Removes switches on R.id entries (not supported anymore from
ADT >= 14)
	6) Introduced a binary dependency (.aar) that replace the actionbarsherlock
sub-module

Remainders:

	1) Change the sub-module back to the owncloud android library
once the PR will be merge