Qt5: Drop QtGui/ prefix from includes
Qt5: Port uses of Qt Threading API
KF5: Initial port to KF5-based build system

Port away from CMake code provided by kdelibs and use macros from the
ECM package.

Not in a compilable state atm. Just touched the build system.
KF5: Port KAction -> QAction
KF5: Port KIcon -> QIcon
KF5: Port away from KShortcut
KF5: Port away from KXMLGuiClient::componentData
KF5: Port away from KMimeType::iconNameForUrl
KF5: Other changes to make compile
KF5: Fix some uses of KAboutData
KF5: Conditionally build some subdirs
KF5: Port to KF5TextEditor
Qt5: KIdentityProxyModel -> QIdentityProxyModel
Remove apparently unused files

Also it's porting to KF5/ThreadWeaver wasn't trivial either.
Port library naming from KDE4_ to KF5::

It's important because it's in charge to propagade the dependencies.
Fixes on the C++ side

Mostly API porting, with "make it compile" as a goal:
- Add headers that weren't included anymore.
- Make sure the porting from KIcon and KUrl is still consistent.
- API changes
- KTextEditor removed interfaces
Disable everything that uses Grantlee for now

It's not available, maybe we should find a fallback for the moment?
Figure out the KComponentData to use

They have to go anyway, but at least have it somewhere specific, at least
until we figure out what we do with the plugin system.
CMake scripts cleanups

${KDE4_*} porting
kde cmake coding style changes
Some changes on moc includes

Without these changes, the combination of automoc+cmake does weird things,
especially if there are private headers involved. My theory is that you
only want /#include "moc_*.cpp"/ headers when there's private slots and
nothing otherwise, but still a theory. Some documentation would be nice.