[3.0.0-wip] Reordering variables that were being used before they were declared. Fixes compiler crashes.

The initial order of the variables would cause compiler issues under 2 of my LESS compilers. The affected compilers were dotless and Sublime's Less Build Package. 

The variables that were causing the issues were:

@dropdown-link-active-bg
@navbar-link-color
@navbar-inverse-link-color

The tests are passing. Verified that the bootstrap.css file was being regenerated, but no changes present due to there being no value changes.