New SemVer compatible scheme:
Following a stable release the hard-coded version will be bumped to
the next patch.
Builds from untagged revisions will have "-dev" version suffix added.
If Git metadata is present it will be added to the version string as well.
This is an attempt to provide a better structure to the project.
All modules are now individual subprojects called libraries.
QxtGlobalShortcut was moved to the Ui library, and resources are part
of the application (app) subproject.
