Added an option to set the :remainder_mark (along the lines of :progress_mark) that allows the user to set the character used to represent the remaining progress to be made along the bar.
Merge branch 'zormandi-master' into development - Closes #52

* zormandi-master:
  Added an option to set the :remainder_mark (along the lines of :progress_mark) that allows the user to set the character used to represent the remaining progress to be made along the bar.