CAUTION: Could be breaking progress bar module changes.

- Bariables for progressbar.

  $bs-progress-bar-height        ?= 20px
  $bs-progress-bar-color         ?= #B76666
  $bs-progress-bar-border-color  ?= $bs-hrule-color
  $bs-progress-bar-border-radius ?= 2px
  $bs-progress-bar-border-space  ?= 1px