semcomedi: fix position of image

now the convention is that in physical coordinates Y goes up, so MD_POS computation must account for it.
gui: Number slider bug fix
Merge branch 'master' of delmic-server.local:odemis
Merge branch 'master' of vpn.delmic.com:odemis
gui lens align: improve dicho search position indication

now correctly computing A/B when magnification changes
prevent long sequences (but need better fix)
Improvement on text.
Fix problems with size of rectangles