modules: updated FindCorrade.cmake from Corrade repository.
modules: populate ${MAGNUM_LIBRARIES} before they are used.

MAGNUM_LIBRARIES are used in all Application classes. I don't know when
this got broken, but now it is fixed again.
Platform: even more doc++.
Platform: initial version of AndroidApplication.

No input events yet.
package: build AndroidApplication in development PKGBUILDs.
Mention minimal required Android version.

We need 2.3 for native_app_glue.