gui: bandwidth slider bug fixes and augmentations
Merge branch 'slider_update'
Merge branch 'master' of delmic-server.local:odemis
gui: new ico_blending_goal image

to be used for the merge slider on mirror alignement
also move goal image to separate folder to avoid being picked up by img2python
gui: improve CCD display on mirror alignement tab

update merge slider icon to goal icon
ensure the images are always at 0,0 , with a mpp depending solely on the sensor pixel size
fit the images to the whole canvas size
Merge branch 'master' of vpn.delmic.com:odemis