Added new parameters to the JSON data

Added muteCamera and muteMicrophone to the JSON data. This will be used
when the user starts up the hangout to set their previous microphone and
camera settings.
Fixed user settings functions

Fixed the functions relating to user settings. Made it so the settings
can be changed within a chat, and also so the settings are passed to
google_hangouts.html when the user clicks the join  hangout button.
Fixed user settings table and functions

Changed the use_microphone and use_web_camera to mute_microphone and
mute_web_camera to make more sense when dealing with the boolean values.
Changed update_user_group_chat settings, added
insert_user_group_chat_settings and user_group_chat_settings_exists