isAndroid: using strings instead, issue #6
not depending on applicationVariants anymore, issue #6
fixed JDK1.7 compatibility, issue #6
bumped version of android plugin.
fixed documentation in RoboSpockConfiguration.
improved handling of android libraries: overcome Robolectric bugs.
moved manifest settings to code.
added test case for android library and explicitly setting android project.
removed setAndroid(String) & setTester(String) due to not possible.
updated changelog & readme to reflect recent changes.
bumped version to 0.3.0