fire onContactStatusChanged only on online/offline changes. not on status changes
finished offline otr
fixed #201
further bullet proofing
moved last seen to contact details
status waiting for images sent offline
offline sending of images
fixed #204
fixed #197
infite scrolling
Add theming, with a Dark and Light theme

 - The light theme remains the default, and should look identical to before
 - Modify the layouts to reference colors in the theme
 - Add an option to change the theme in the preferences (note that this does
   not take effect in already running activities)
 - Modifiy the ConversationActivity as the secure drawable for the action bar
   is not handled in the layout
 - Modify ConversationFragment as the text color is not handled in the layout
 - Add calls to setTheme in the activities
Set current theme for the ManageAccountActivity

Previously was hardcoded to the dark theme
Include the ic_action_new_attachment icon in the styles
Remove some redundant logging
Include the ic_action_group in the style

Used for the conference details button
Use a lighter background for the chat bubbles
Make the conversations overview divider themeable
Separate theming in conversation_list_row

This allows for making the secondary text darker in the dark theme.
Allow theming for the account_row layout
Theme the sliding pane shadow