Implemented comments from Paulus.

Revised main to use frontend and demo strings rather than importing
their domains.
Removed submodule validation.
Moved local library mounting to the bootstrap module and out of core.
Added requirements_all.txt for all dependencies.
Made core dependencies looser.
Small updates to setup.py.

homeassistant/core.py

@@ -666,10 +666,6 @@ class Config(object):
         # Directory that holds the configuration
         self.config_dir = get_default_config_dir()
 
-    def mount_local_path(self):
-        """ Add local library to Python Path """
-        sys.path.insert(0, self.path('lib'))
-
     def path(self, *path):
         """ Returns path to the file within the config dir. """
         return os.path.join(self.config_dir, *path)