Merge pull request #12 from Susurrus/master

Added a "format" to messages
filterTableWidget: added a separate column for checkbox since checkbox/text pair was giving problems.
Also fixed a bug in outmessage.py where ...[field].units should have been .unitsConversion
CLI mode - when an invalid units conversion happens, give the user a list of valid options
User can now pass in command line arguments for port and message file when using GUI
Filtering done in the tablewidget now more robust
small bug in units conversion in outmessage.py
small bug in units conversion in outmessage.py
Filtering by node ID works
Filtering by node ID works
In metadata file, allow for no units in a field
Added description string to the ViewMetaData tree
Added comments, improved logging UI
added tooltip to filterTable
displayList dict no longer using string compare, instead using enum at top of outmessage.py
some comports code, no big change
Transmission: when user doesn't input anything into a field, we will assume it to be a 0, and update the LineEdits accordingly
Transmission: Added a check for proper bit length for each field
Transmission: almost there
Transmission: algorithm seems correct, now need to test on Bryant's corner cases
Commented the generateMessage function