Rename parser and its testfile to argparser

This is in anticipation of another parser module for the mp3
titlestring.
Refactored basically everything out of vid2mp3.rb

Also renamed parser to argparser to make way for different parsers...
Added gemfile
Added Rakefile to handle tests
Add titlestring parser and test file

This module accepts youtube title strings in artist - title (possibly
notes) format and breaks it down into a hash for use. Also returns
extension
Add downloader and handler modules

Handler module is passed the chosen behavior and delgates
responsibility.

Downloader module interfaces with viddl-rb to get names and urls.
Added filename generation to titlestring parser
Update titlestring parser filename generation to remove spaces from artist
Add presenter module

Added a module which contains all printouts and also an edit loop to
allow the user to edit our track info hashes.
Update titlestring parser to use video extension

It was appending ".mp3" but it's too early for that...
We're currently downloading a video and need the extension still for
ffmpeg to load it correctly.
Add video download function to Download module
Update presenter edit loop to allow blank response as confirmation
Update downloader module to actually return the path it saved file to.
Add open-uri and taglib to gemfile.
Add logic to add notes to title in TitlestringParser
Add converter module which calls out to ffmpeg.
Add tagger module which updates mp3 with title and artist.
Add SAVE_PATH constant to vid2mp3.rb user config section
Update handler with full logic for download command.
ark