[tests] Initial commit

Note: when built with Qt5, the warning
"QDBusConnectionPrivate::disconnectRelay called for a signal that was not
found" is issued a number of times - this is fixed in recent Qt versions.

Relates NEMO#684
Workaround QSignalSpy error with QDBusInterface

QSignalSpy and QDBusInterface do not work well together because
QSignalSpy uses internal version of QObject::connect() which (in
contrast to the public version) does not call QObject::connectNotify()
on sender. QDBusInterface relies on connectNotify() to connect the D-Bus
signal immediately when QObject::connect() is called.

Relates NEMO#684
Do not set OBJECTS_DIR & MOC_DIR qmake variables

Using variables like these makes usage of 'lcov' coverage analyzis tool
impossible. Please consider using qmake's support for shadow building
instead:

  cd build/ && qmake .. && make

Relates NEMO#684
Add 'coverage' make target

Relates NEMO#684