fixes #3210: add .btn to .navbar-form to remove bottom margin, improve vertical align of contents of .navbar-form

Rather than having a partial reset with individual elements having
their styles built back up, only elements without replacement
styles have specific properties 'reset'.

This commit also includes: a correction to the font mixin arguments
used on forms (the output is now valid CSS); the removal of
`overflow-y:scroll` from the `html` element which is now known to
cause some problems for jQuery modal plugins in Firefox.

breaking out patterns.less even more, removing unnecessary div from checkbox and radio lists--now just labels and inputs

updated fluid example to not use floated sidebar and instead use position absolute; not ideal, but it works in most cases

refactor fluid layout to be more specific to not interfere with modal content while adding right sidebar option

update variables to inlude @baseFontSize, @baseFontFamily, @baseLineHeight for easier customization; added placeholder for @primaryButtonColor, but didn't implement

overhaul the grid CSS to make it more durable for tables and forms to use the same sizing methods; need to see about improving this in the future

updated table styles a bit and floated the fluid columns to clear the row dropping problem we were having

comment out box-shadow on masthead and footer in docs.css because Opera sucks at inset box-shadow :"

remove theme.less and split preboot.less to mixins.less and variables.less to isolate customization from function

remove qualifying tags in .span selectors for built in grid so that we can use .span-n classes in form styles

overhaul docs CSS since it was scalable, converted docs mastheads and footers to classes and HTML5 elements, add masthead to js docs page but make it slate so it looks cool and stands out