After all I don't need all that stuff in the cmakeplugin, all i needed
is now bundled in debugginghelper.h/cpp

And add a instance() method to it.

The Debugger, cmake and Qt4 plugin all need it. More refactoring to it
coming.

Task:     247566
RevBy:    dt

Many singletons have their own instance() method, in which case there is
no need to use ICore::instance() to get access to them.

replace ExtensionSystem::PluginManager::instance()->getObject<Core::ICore>() by Core::ICore::instance()

Dependencies between projects can now be edited in the Projects mode.
You can simply check for each project the projects that it depends on,
and they will be built first. A message box pops up when you try to
create a circular dependency.

Could use some testing.

Details:  ProFileCache be gone, as is ManagedProFile, not to be missed.
Drastically simplified how ownership works.