Fixes #5471: Remove color from .navbar and .navbar-inverse and reassign to .navbar-text to prevent unintended cascading

add new vars for common border-radius, upping border-radius of inputs to 4px; add border-radius changes to -large, -small, -mini for buttons and paginations

add new vars for common font-sizes and paddings with large, small, and mini components; resize pagination and buttons to better match each other

https://github.com/twitter/bootstrap/issues/4508

should fix this issue

fixes #4044: make z-index of tooltips same as fixed navbar so they overlay it if generated from within

update button styles to use updated 14px base font size, align carets to others with no opacity changes

fix dropdown vars and make hover state be link color again, add gradient to dropdown link hovers, fix caret positions and active states on nav tabs, tweak nav link padding