Make version number adhere to distutils.version.StrictVersion rules

mopidy/__init__.py

@@ -1,7 +1,7 @@
 from mopidy import settings as raw_settings
 
 def get_version():
-    return u'0.1.0a0.dev0'
+    return u'0.1.0a0'
 
 def get_mpd_protocol_version():
     return u'0.16.0'

tests/version_test.py

@@ -0,0 +1,15 @@
+from distutils.version import StrictVersion as SV
+import unittest
+
+from mopidy import get_version
+
+class VersionTest(unittest.TestCase):
+    def test_current_version_is_parsable_as_a_strict_version_number(self):
+        SV(get_version())
+
+    def test_versions_can_be_strictly_ordered(self):
+        self.assert_(SV(get_version()) < SV('0.1.0a1'))
+        self.assert_(SV('0.1.0a1') < SV('0.1.0'))
+        self.assert_(SV('0.1.0') < SV('0.1.1'))
+        self.assert_(SV('0.1.1') < SV('0.2.0'))
+        self.assert_(SV('0.2.0') < SV('1.0.0'))