Early work on integrating a new QML-based interface

Somewhat functional contact list, very little else works at present
Dead code removal as part of the UI transition
Add chat text and input to the QML UI
Add missing license headers on QML files
Delete unused UI images
Trivial compilation fix
Compile fixes with QT_NO_DEBUG.
Added a provider for avatars in the new UI

This will need something added later to allow for cache invalidation, and there is currently still no way to set or receive an avatar.
Fix focus and pasting rich text for the chat input

ContactPage is now a FocusScope, where the chat input has focus. The scope is given focus when the page is made visible. More focus work is required for popout windows.
Add TopLevelWindow to allow specifying and controlling other windows from within QML.
Workaround QTBUG-10683 on the context menu for the chat text area
Implement a pure QML add contact dialog

This is much prettier than the old dialog, and is integrated with
the new interface. Patched qt-components-desktop is required to use.

See https://qt.gitorious.org/~special/qt-components/special-desktop-components
Ensure new contacts are in the RequestPending status when added
Defer text styling on ContactListItem until the highlight rectangle is underneath

This provides a slightly nicer look during long animations of the
highlight rectangle
Fix a minor regression from the ContactListItem text change
Fade avatars for offline, inactive users in the contact list
Add a way to programmatically set the current UI contact
Minor UI tweaks and fixes
Prevent an assertation due to a late state change after an accepted OutgoingContactRequest
Squash QML warnings