Fixes app path issue which lead to build fails. Fixes #13

* The build fails when there is a space in the Application path.
* This small fix resolves that issue.

buildozer/targets/android.py

@@ -548,7 +548,7 @@ class TargetAndroid(Target):
             '{python} build.py --name {name}'
             ' --version {version}'
             ' --package {package}'
-            ' --{storage_type} {appdir}'
+            ' --{storage_type} "{appdir}"'
             ' --sdk {androidsdk}'
             ' --minsdk {androidminsdk}').format(
             python=executable,