QmakeProjectManager: various renaming cleanup

Change-Id: I0433317d03aefb8e175f2208ca7ae29fa3e9fa49
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>
QmakeProjectManager: De-noise qmakerunconfiguration.cpp

Change-Id: I14971be5c00da949ff46729236c535d1ac29f9bc
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>
Debugger: Remove dead code from GdbEngine

Change-Id: Ibd5a5e5a80bb31b798b26b340fae460fdded7892
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>