Added the theme manager, fixed some UI issues, updated copyright notices.

Added the theme manager, the new "Terminal" theme, and updated the
default theme to contain the XML header required by the new theme
manager.

Fixed the docking of the tree view in the favourite servers dialog to
fill the panel instead of anchoring incorrectly.
Fixed an alignment issue and the sending of blank messages.

Fixed an alignment issue with the default and terminal themes and
prevented the sending of a blank string.
Changed themes dialog to close when the escape key is pressed.
Merge pull request #10 from intninety/enhancement/theme-manager

enhancement/theme-manager