remove modal-open class
hopefully resolve z-index headaches

fixes #5102, #5166, #5194, #5205: add overflow: visible; to .nav-collapse.collapse so that dropdowns overflow correctly in the navbar in IE7-8

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

fixes #5177: remove color on .btn-large .caret, but keep sizing change; also start to add CSS tests for buttons

fixes #5041: add new navbar css tests for each variation, remove width: 100%; from .navbar-static-top

Updated pagination to support .pagination-large, .pagination-small, .pagination-mini matching button sizes. Updated related docs.

fixes #5040 manually: remove overflow: auto; from .modal to resolve sporadic modal right padding issues with scrollbars