Initial documentation of several controls.
fix stroke of MetroCircleButtonFocusVisual
Finishing up the first pass on documentation.
Documented Accent, Theme and ThemeManager.
Merge pull request #748 from Amrykid/amry-documentation-r1

Code Documentation
minor changes to Scrollbars

cose cleanup and set VerticalScrollBarButtonHeightKey to 50
fix TextBox ScrollBar issue

- if a TextBox becomes multiline and it was resized, the ScrollBar goes
away
- introduce ButtonWidth to set the TextBox, ComboBox buttons manually
(default is 22, 24)
much better multiline TextBox handling
gray7 was missing; caused xaml parse exceptions
Merge pull request #751 from Icehunter/missing-gray7-baseLight

gray7 was missing; caused xaml parse exceptions
dark and light theme should always re-set the same brushes
#752 check if Owner not null