replace reboot/normalize monospace hack with monospace system font stack

Created by: client9

There are two stanzas (selectors) for code, kbd, pre, samp in the main bootstrap distribution

The first in reboot:

code, kbd, pre, samp {
  font-family: monospace,monospace;
  font-size: 1em;
}

And then later in bootstrap:

code, kbd, pre, samp {
  font-family: SFMono-Regular,Menlo,Monaco,Consolas,"Liberation Mono","Courier New",monospace;
}

The proposal would be to move the system monospace font stack into reboot and get rid of the monospace, monospace hack (more details of which can be found here: https://github.com/necolas/normalize.css/issues/695 ). I think this would make reboot more consistent (since sans-serif font uses system stack), be more clear, and make bootstrap smaller.

thoughts?

regards,