Attribute customui value display

[BryonLewis]

resolves #493

• udpates the old displayValue under th Attribute Shortcut Button display to be in a new Section 'Custom UI'
• This has controls for:
  • displaying just the value even if no buttons are set
  • customizing the header
  • Setting Sticky Value (value persists until it is changed), with some sort of indicator for when it is on a frame value
  • Alignment for the value, fontsize
  • Append/Prepend labels for the value
  • Ability to set the value color to custom color, or to inherity the attribute value color
  • Header display options
  • Long/overflowing text display options.