So far the backend libraries' include paths were relative within this
repository. This means the header files could not be used at their
installed location.
This change replaces them with "<>" includes to fix that problem and adds
a new include directory so building everything at once still works.
With this change it should be easier to actually split some parts into
another repository if this one would become too big.
* Support triggering actions via the context menu in the regular tray like
it is already possible in the Plasmoid
* Support copying via the context menu in the Plasmoid like it is already
possible in the regular tray
* Reduce repetition of coding patterns using templates
Map context menu coordinates to top-level widget if the top-level
widget is a QMenu. Otherwise the context menu is not displayed at
the right position. Not sure why this workaround is required.
The check for QMenu is required. Otherwise the "windowed" mode
enabled via --windowed CLI argument would not work anymore. In
this mode the top-level window is a regular window.
Adding the window flags Qt::Sheet or Qt::Dialog to the QMenu
would help as well but that prevents closing the menu (see
https://github.com/Martchus/syncthingtray/issues/41).
Martchus