Remove color: inherit from headings

Heading classes (`.h1`, `.h2`, etc.) override default color styling for anchor tags as well as other well-defined classes for color styling (`.text-success`, `.text-danger`, etc.).

The following code snippet when rendered would appear with `@text-color` (instead of `@link-color`) until hovered over at which point it would appear with `@link-hover-color` color.

    <a href="#" class="h1">Heading 1</a>

It should be noted that this styling was correct shortly ago in BS 3.0.0.  I have included two examples to document the issue:

Bootstrap 3.0.0 (styled correctly): http://jsfiddle.net/MYrV4/3/
Bootstrap 3.0.2 (styled incorrectly): http://jsfiddle.net/5g7WH/2/

Heading classes (which are simply meant to emulate their respective heading sizes) should not affect the color of anchor elements nor elements with the .text-* classes.

While related to Issue #10202, I view this to be a far more grievous issue than it as it is more far-reaching (affecting styling all the way down to basic anchor tag styling).