Add current system MSYS check (#278)

Author: bonfy

Diff for: fire/console/platforms.py

@@ -153,6 +153,8 @@ def Current():
       return OperatingSystem.MACOSX
     elif 'cygwin' in sys.platform:
       return OperatingSystem.CYGWIN
+    elif 'msys' in sys.platform:
+      return OperatingSystem.MSYS
     return None
 
   @staticmethod