Gtkwrite Version 0.0.7 - development release

Additions of Toolbar Appearance (submenu) allowing selection of Icons, Text, or Both Icons & Text. Addition of Edit->Select All and Edit->Deselect All with cursor return to the original mark. Code cleanup removing all Toolbar callbacks and accelerators. There is no need to duplicate code for a toolbar callback implementation, Attach menu callbacks instead. Removed toolbar accelerators as the shortcut is provided through the existing menu accelerators. Updated find scroll_to_mark to position the matched text at 80% of the textview to provide visualization of the context following the match. Removal of all duplicate code.