Issue 544 bugfixes

[afshin]

These are bugfixes for #544

• Color picker widget respects widget width
• Dropdown widget respects widget width
• Progress bar widget renders 'vertical' mode correctly
• Fix Dropdown widget keydown handler inside notebook

cc: @jasongrout @SylvainCorlay

[afshin]

[afshin]

FYI, I added the .fa class back in for button icons.

[jasongrout]

Darian, those changes look good; thanks. One more thing about the dropdown - if the size of the dropdown has changed, the actual dropdown list no longer matches the width of the control (see the image below - the grey box is a different width than the control). Can we get the list to match the width of the control?

[afshin]

@jasongrout Good call, the drop list width needs to be calculated at run-time in JS (it used to just be a static 300px).

[jasongrout]

Nice, thanks! I also investigated a bit more deeply what the <select> behavior is on different platforms over in #562. No conclusions there, but there is precedence for having the dropdown list box width be more than the dropdown control size.