Add feature to support navigating to a specific column and line, as well as specific line.

Also added:

 - :white-check-mark: Add a test for behavior when line entered exceeds number of lines in the buffer.
:lipstick: Make code slightly simpler by using the coffeescript question-mark operator and Editor.row.
Merge pull request #17 from jwir3/master

Add feature to support navigating to a specific column and line, as well as specific line