Fixed time range misbehavior of iter_by_timepoints
Add skipping existing data feature for iter_by_files
Initial commit for the derandomization GUI

We begin with a setup that has the basics for image zoom/pan and a visualization
of the csv file. We also have two buttons that add images and csv files.
* util/derandui.py (DerandomizeGUI): New class that will hold all logic for the
derandomization gui.
(PanZoomGraphicsView): New class for visualizing images with pan and zoom.
* util/derandui.ui: This is the skeleton of the GUI. File produced by "designer"
(Qt's gui designer).
Add time stream list.

* util/derandui.py: Add GPL text.
(timeStreams): Dictionary that holds all the opened timestreams.
(onClickTimeStreamList): When we click on the "+" symbol we add a timestream
directory. We fail with an error message is TimeStream.load fails.
* util/derandui.ui: We add the timestream list as a TableWidget to the user
interface. We add a hidden colomn to relate the rows in the timestream list to
the new self.timeStreams dictionary.
Remove frame margin.

* util/derandui.ui: So we can give more space for the timestream list, image and
csv table.