init: don't set configuration from android if we are in the "documentation" mode

+ use ANDROID_ARGUMENT availability in environ instead of "import android" for detecting the android platform: sl4a have their own android.py too. Closes #719

kivy/utils.py

@@ -12,6 +12,7 @@ __all__ = ('intersection', 'difference', 'strtotuple',
            'interpolate', 'OrderedDict', 'QueryDict',
            'platform', 'escape_markup', 'reify')
 
+from os import environ
 from sys import platform as _sys_platform
 from re import match, split
 from UserDict import DictMixin
@@ -332,11 +333,9 @@ def platform():
     global _platform_ios, _platform_android
 
     if _platform_android is None:
-        try:
-            import android
-            _platform_android = True
-        except ImportError:
-            _platform_android = False
+        # ANDROID_ARGUMENT and ANDROID_PRIVATE are 2 environment variables from
+        # python-for-android project
+        _platform_android = 'ANDROID_ARGUMENT' in environ
 
     if _platform_ios is None:
         # TODO implement ios support here