Add bootstrap color picker for choosing hex values.
Add before save in color model to upcase hex value. Closes #15.
Disable page scrolling when modal dialog is shown.
Make color band on colors index page wider.
Preview the color of the group when changing option in select.
Move database query from group form view to controller.
Change class name on colorpicker text fields.

This is to avoid potential conflicts with the .colorpicker class used
for the actual colorpicker elements inserted by the plugin.
Merge pull request #17 from msrose/feature/colorpicker

Feature/colorpicker