Add better documentation in style guide.
Updated description in README.
Merge pull request #360 from DFurnes/docs

Add better documentation in style guide.
Remove old button overrides from header pattern.
Header pattern cleanup & added "centered" modifier class pattern.
Merge pull request #361 from DFurnes/header-refactor

Header refactor
Create reusable text shadow variables.
Fix visual bug with disabled button active state.
Make button focus state more visible.
Add focus state to style guide for text inputs.
Add IDs to style guide modifier examples for linking/styling.
Clean up style guide styles.
Add dark background for patterns which require it.
Merge pull request #362 from DFurnes/cleany-clean

Miscellaneous cleanup
Fix error when no scroll indicator links are on page.
Merge pull request #364 from DFurnes/scroll-indicator-error

Fix error when no scroll indicator links are on page.
Release v5.1.2
Built assets for v5.1.2
Built style guide for v5.1.2