gui: VisualRangeSlider bug fix
gui: Small TextViewOverlay bug fix
gui: StreaPanel Layout bug fix, which was responsible for GTK error messages being printed to console
gui: Put 'nm' on the list of units that should not be SI formatted
gui utils: new ProgessiveFutureConnector

to connect a ProgressiveFuture to a progress bar.
Now only used in the SPARC acquisition but should be usable in a couple more places...
acq futures: ensure that SimpleStreamFuture.result raises an execption if cancelled

It could happen that result() returns before the cancel state is fully set, causing the future to
report incorrectly that the task finished fine after it was cancelled.
gui acquisition: use ProgessiveFutureConnector SECOM acquisition window

This simplies a bit the code.
model futures: ProgressiveFuture.add_update_callback always immediately report current status

sometimes there is never new info, so it's really important to get immediately the progress status.
gui util: correctly update the progress bar when new information is given

Keep increasing the time passed based on the last information received.
This will allow to remove the fake progress update from the acq mng.
gui tab: use ProgessiveFutureConnector for fine alignment progress bar

seems to work...
acq mng: remove trick to force time update

Now the GUI does it correctly, no need for tricks, and we can follow the API as normal
Merge branch 'master' of vpn.delmic.com:odemis