Made solid pill labels look less like buttons

Using a lighter background with darker text making the solid pills look:
-less bold/contrasty
-less like tapable buttons

Also updated _pillLabelFactory.scss so all you have to do is pass a color into the solid_pill mixin, but kept $bgColor and $textColor params incase you want to do something custom.

@akdetrick, feel free to reject the changes I made in _pillLabelFactory.scss if you think the old way works better.