release: version 0.7.4

* change version strings/numbers to 0.7.4
* disable HTML_TIMESTAMP for doxygen
* don't build tests with make all

Signed-off-by: Matthias Kretz <kretz@kde.org>
after release: version 0.7.4-dev

* change version strings/numbers to 0.7.4-dev
* enable HTML_TIMESTAMP for doxygen
* build tests with make all

Signed-off-by: Matthias Kretz <kretz@kde.org>