Extract messages from header file as well, optimize extraction

effects/Messages.sh

 #! /usr/bin/env bash
 $EXTRACTRC `find . -name \*.ui` >> rc.cpp || exit 11
-$XGETTEXT `find . -name \*.cpp` -o $podir/kwin_effects.pot
+$XGETTEXT `find . -name \*.cpp -o -name \*.h` -o $podir/kwin_effects.pot
 rm -f rc.cpp

kcmkwin/kwindecoration/Messages.sh

 #! /usr/bin/env bash
-$EXTRACTRC `find . -name "*.ui"` >> rc.cpp || exit 11
 $XGETTEXT `find . -name "*.cpp" -o -name "*.qml"` -o $podir/kcm_kwindecoration.pot
-rm -f rc.cpp