Adapt to the translation infrastructure

Adapt to the changes in liblxqt. We now use the LxQt::Translator class to
load the translations. We save a few bytes ditching lxqttranslate.h
Trim input text. Fixes lxde/lxde-qt#139
Add Ctrl-p and Ctrl-n movement shortcuts.

Ctrl-p moves the focus one item up and Ctrl-n moves the focus one item
down.
Port lxqt-runner to KWindowSystem. Purge Qt 4.
Fixes lxde/lxde-qt#311, FTBFS
CMakeLists cleanups
Fix QDesktopWidget::availableGeometry() vs KWindowSystem::workArea()
bug

Special thanks to Martin Graesslin
Fixes dialog type, alt+tab won't focus it