x86_64: minor bignum performance boost

Incorporate a few x86_64 assembly routines from the latest GMP,
which provides a small speed boost for operations such as bignum
multiplication and division.
add syntax/wrap-modbeg
scribble/manual: break `defthing` output lines if needed

If the defined identifier plus contract doesn't fit on a single
line, put them on separate lines.
scribble/manual: improve `defstruct` layout

The old layout used column spans that created ugly space around parentheses
for some combinations of field-name and keyword-modifier lengths. The new
layot avoids the problem by breaking the keyword modifiers into their
own table.
Adjust rewrite-side-conditions/check-errs so that it
returns the ellipses names in addition to the regular names

keeping the names in the pattern and including them in the last
two results

closes PR 14291
adjust bitmap test to just show the diffs right away

(because it is a lot faster now than it used to be, thanks
to earlier improvements)

Also, Rackety
some small changes to the fonts (perhaps for the update to osx 10.9)
doc clarification on init-auto-scrollbars
adjust the source location on metafunction def-before-use errors

closes PR 14289
Fix types for `process` and `process*`

Closes PR 14297
Fix type inference helper on AnyValues range

This bug allows a test to be written for the previous
commit. Previously, it would throw a match error.
Fix doc typos
Remove unnecessary keyword from generics examples
Cleanup parse-type.

Add syntax class for @ and !.
Add use literal sets.
Make full-latent cleaner.
Split out implementation of define-literal-syntax-class.
Make parse type use literal-syntax-classes.

Fixes arrows in check-syntax.
Adds actual bindings for Top and Bot filters.
Make tests give more info on failure, and change test to not use Number.