GUI: Moved file data conversion to static streams from the tabs module to the StreamController class
GUI: Updated the loading and displaying of file data
model: introduce IntContinuous

Both Int and Continuous.
Will be needed for SpectrumStream.width .
GUI: Viewport button thumbnail fix *WIP*
acq stream: support width in spectrum stream 1D

Based on example Matlab code from Toon Coenen.

Not yet fully tested on real data, but seems to work.
Merge branch 'master' of vpn.delmic.com:odemis