Replaced slashes with file.separator in order to pass the test also on Windows.
Unfortunately I cannot test it on Linux.

Signed-off-by: Diego Costantini <diego.costantini@gmail.com>
Added a condition to build.xml to find maven in windows (and Linux - to be tested).
On windows, find sdk location by looking into ${env.ANDROID_HOME} since find-android.bat does not work.
Merge pull request #410 from cowst/bug/separators

Replaced slashes with file.separator in order to pass a test on Windows
Use File join rather than string appends for Windows FS compat.
Merge pull request #411 from cowst/bug/fix-build-for-windows

build.xml fixes for windows
Changed to compat v11 and added setLayers
Merge branch 'robolectric-2-master' of github.com:pivotal/robolectric into robolectric-2-master