gui: reduce logs

now things are working, most of the log is more confusing than helpful
gui: Connected all PointSelectOverlays to the same VA in the StaticSpectrumStream
gui: small bug fix that makes sure any hover effects are cleared from the PointSelectOverlay when the mouse leaves the canvas
gui: Disabled sem/optical button images added
backend: add support for configuring the pole position in the SPARC

This position cannot be computed unless the position of the lens (X/Y) is known.
After discussion with Andries & Wouter, it seems actually easier for the user to
just enter the position of the pole on the CCD (when the lens is set).

So extend the Lens component to support bearing this information, and mdupdater
to set the metadata of the image.
gui: now actually with the added images added
gui: new spectrum and angular buttons
gui: button tweaks
gui: Updated XRC file
gui: bug fix for SPARC gui
acquisition: add support for AR/SEM acquisition

barely tested
acqmng doesn't seem to save yet with multiple images in .raw
Merge branch 'master' of vpn.delmic.com:odemis