Update Qt.gitignore
- Ignore '*.moc' files (foo.moc created when foo.cpp contains a Q_OBJECT.)
- Ignore '/.qmake.cache' and '/.qmake.stash' as does the official Qt Creator project.
Merge pull request #1002 from munkhoff/qmake-stash-and-dot-moc

Update Qt.gitignore with rules from qmake