Force font selection on controls sample (to check font family works ok and to avoid default font -that can be different in wxQT than in wxGTK-)
Implement slider tick frequency and marks in wxQT
Fix slider event in wxQT, now using valueChanged signal as tracking is enabled by default. Note that using sliderMoved only works for mouse events (not for keyboard ones), and don't catch the final value when released (slider didn't reach 100%). Also, removed a comment copy-pasted by mistake.