Prevent menu button color inheritance.

Buttons within .ui.menu, that are styled above anchor (`a`) tag, are colored inappropriately.

This fixes it.
Fixed labeled menu icon button icon positioning.

A .button.labeled within .ui.menu > .item has icon vertically aligned closer to bottom, not middle.

This fixes it.
In-Menu input action button corrections.

Action button within menu had some sizing and positioning issues.

This attempts to fix it.

Tested with large, normal, small menus; .button, .icon.button, .labeled.button. All 9 combos.
Merge branch 'master' of https://github.com/joltmode/Semantic-UI
Merge branch 'master' of github.com:Semantic-Org/Semantic-UI
Updates menu less slightly to include css with similar rules #553