Hierarchy, Colors, Padded Labels

Added features: Progress bars can nest. Labels and progress bars can be colored.
Labels are padded to be equal length.

Added

• Progress Bar Hierarchy/Indentation
  • PromiseBar.all stores a reference to the related Progress in the returned Promise
  • Progress finds progress-bar children on initialization
  • Progress#indent returns the indentation that should proceed the progress bar
  • Progress#draw draws descendants
• Color Formatting
  • ANSI codes are ignored when calculating bar length, so label and other fields can have color codes
  • Added barFormat option, which can transform the bar (add color, etc.)
• Optionally pads labels to make labels an equal length.
• Documentation published to gh-pages.