Refactoring - Renaming variables

I just can't stand abbreviated variable names
Added some input validation

Added basic argument input validation
and some minor refactoring
Removed the GetInputFilename function

As it's no longer required
Fixed the wrong length check of the arguments

Should have been != 1
Added basic progress indication

Indicating the line currently being processed
Merge pull request #1 from timothyparez/master

Some basic refactoring, input argument validation and progress indication