gui settings: fix show_panel to accept boolean

Follow the same behaviour as .Show() which show_panel() wraps.

Fixes the calibration file selectors on SPARC.
gui gallery: add support for spectrum background file

The spectrum need to be subtracted to a background before the efficiency correction can be really used.

This is only the GUI part. For now it will fail as the stream doesn't support background subtraction.
Merge branch 'master' of vpn.delmic.com:odemis
doc: update GUI editing instructions

Now that the xrced launcher is more clever, there is less things to do :-)
acq calibration: support background data for spectrum

The basics is there to load background data and subtract it.

Need more test cases, and to connect it in the streams.
History overlay test case fix
Made the HistoryOverlay use a stage_history VA provided by the microscope model to keep track of positions.
Small history trail rendering tweak to improve clarity in the overview button.
Small update on the embedded HTML document window, after checking whether the 'fake' import is still needed in wxPython 3.0 (which is, and probably will always be, the case)
Moved overview and stage history logic to separate OverviewController class
Added tooltips to settings labels
acq stream: finish implementation .background for the SpectrumStream

Needs a formal test case, but it seems to work.
acq calibration: use average when a background spectrum has shape XY > 11

As remarked from Chalmers, this is handy to reduce noise when doing background acquisition.
gui tabs: log error if calibration file is incorrect
cli: add auto-completion to odemis-convert

also add description to the spectrum efficienty data for user info.
acq: add more test cases for calibration

still passing.
acq: fix spectrum calibration

Need to reset correctly the stream data if set to None.

Fix comparaison of float values in numpy.
driver pigcs: add basic support for command over IP

At least it can initialise with the IP address explicit.

Pretty much no error handling is working.
LensAlignment integrated, hole detection simplified
PatternScanner moved to separate class