Add Bootstrap Progress Bar

[tryexceptpass]

Create a ProgressBar object that wraps div with progress and contains another div with progress-bar and `role="progressbar".

• Include mechanism with which to set aria-valuenow, -valuemin and -valuemax attributes.
• Support adding label text
• Provide method for setting min-width
• Allow severities through progress-bar-success, -info, -warning, -danger.
• Support progress-bar-striped setting
• Include active for animating striped bars
• Support stacked with multiple progress-bar divs.