Todo.txt

- Need to implement parsing for print
- Should combine the LineRange option with an int value that has the different
  ways a count can be combined with a Line Range
- Global count and range
- Should ;global move the caret to the start of the line?  How do commands which 
  don't take a range behave?
- Global should work in an undo transaction
- Maybe ? LineRange needs to be taken out of LineCommand.  It shoud be an indpendent 
  which is passed down.

  Maybe not.  How will this work with end counts?
- I think every "Some lineRange" in Parser.fs should just remove the option from the node.  Maybe
  the option should go await entirely and instead we add an Unspecified / Default member
  to LineRange.  No loss of fidelity there

  this would also solve the issue of conveying a default.  Some commands default an
  empty range to the curret line and others the entire buffer
- test :global / print moves the caret
- :global should be passing an empty SnapshotLineRange down to each of the LineCommand 
  values and not the current line.  The command itself must interpret the default case
  and provide the appropriate value.   This can be proven by doing a :g with a command
  of retab.  It will retab the entire file not the lines that match. 
  
  That's going to take some work.