Rename .hero-unit to .jumbotron becaue fuck dashes in filenames and sports metaphors are cooler than ad ones

* Deprecate .input-append and .input-prepend
* Use new, single base class for component, .input-group
* Deprecate .addon for .input-group-addon
* For compatibility with all buttons, require .input-group-btn to wrap buttons and button dropdowns
* Still need to reimplement with segmented button dropdowns, but that's dependent on a refactor of those first

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