Remove add/remove class methods,
Remove helper set/get css methods
Fix tests
Initial crack at using specific traits for styling.
Partial implementation of styles
Finished style attributes.
Fab CSS
Updated widget examples for recent changes and,
renames from earlier PRs
Fix some bugs found by the widget examples,
add margin and padding base traits,
add overflow traits to box base.
Added Bootstrap specific classes,
and fixed a few bugs here and there...
Added bootstrap3 progress bar classes
Remove references to add/remove_class methods.
Fixed rebase bugs and other bugs.
Fab CSS
s/fore_color/color
s/back_color/background_color
Tabs->Spaces
Cleaned up hbox and vbox widget div styles,
removed 5px margin
fab css
Remove forgotten hreadout
fab css
Update examples, fixing bugs found in review.