Removed unintentional space in Downlite title

It was causing an error in some older YAML parsers for some reason.
Added Browser Installation Checks & New Executable

Added checking for installations of Firefox and Chrome before cleaning
them  since the program seemed to be failing if one wasn't installed.

Also added the executable rmart to start the program. This will make
testing rmart.rb file a lot easier / possible =)
Updated README to reflect new instructions