Add QtCreator project files
Compile AWN using C++ compiler. C API is still exported
Use C linkage for exported APIs
gitignore: Update
taskmanager: Move common enum to a header
taskmanager: Wrap wnck include into extern "C"

One header in wnck is not wrapped with extern "C", thus we will get
linker errors.
Fix wrong forward declarations
Fix gotos jumping through an initialization of a variable
Fix enum cast
Update QtCreator project file
po: Add notexist file
Reformat the codebase
make: Enable C++11
make: Depend on gtkmm
README: Remove dead links
panel: Resize the panel on screen geometry change