Replaced the GUI task setup when launching the application with 
command line options passed to validate.py.
Merge pull request #73 from drusk/launch_cl

Launch from command line
Added get_unprocessed_sources method to WorkUnit, which is used to
only download images for unprocessed sources. (saves a lot of time
when starting up a partially processed file).
Merge pull request #77 from drusk/partial_downloads

Only download images for unprocessed sources
Use cadc shortcut in vos clients to avoid some connection overheads.
Merge pull request #79 from drusk/vos_shortcut

Use cadc shortcut in vos clients to avoid some connection overheads.
Fixed problem when processing candidates where next_item only 
went to the next source, not the next unprocessed source.  This meant 
when reloading from partial progress in a file you would only get bumped 
up to the second source, and if you had really already processed that one
it wouldn't get downloaded again.  Therefore you were left with an image
loading dialog forever.
Merge pull request #81 from drusk/cands_load_ff

Loading partial progress for candidates now fast-forwards
Made image downloading multithreaded.
Merge pull request #83 from drusk/multithreading

Made image downloading multithreaded.
Made apcor data optional for DownloadedFitsImages.  Trying to do
photometry calculations on them will just raise a ValueError.
Apcor files are now only downloaded for RealsWorkUnits.
Decreased max download threads to 3.
Added method to SourceReading for calculating the offset between 
their coordinate systems.
fixxed the RA/Dec scale for plotting so they only match 13A blocks
Merge branch 'master' of https://github.com/ijiraq/MOP
created a per task work flow, each job submitted individually
The image slice downloader now centers cutouts around the middle
observation of a source.
Reduced field of view to 250 by 250 pixels.
Merge branch 'master' into fov_centering