add two (hopefully) color-blindness friendly color schemes

based on Paul Tol's palettes, found here:
http://www.sron.nl/~pault/
Fix benchmarks to not use `collection-path`.
Make `profile-lib` a single-collection package.
Clarify the data definitions used by drracket for stacktraces.

In particular, it is not the same format as errortrace uses internally.
Remove dead code.

Not only is `st-mark-bindings` documented to always return `null`,
but DrRacket does not use `make-st-mark` to insert bindings in the
first place.
Remove one-armed `if` handling.

This is no longer possible since #%kernel `if` requires two arms.
Required identifiers cannot error on use.
Implement statistical errortrace-based profiling.

Add a mode to the profiler to use continuation marks inserted
by the errortrace annotator instead of the runtime.

Split `syntax/source-syntax` out from Typed Racket as a separate package,
and use it to give better names for errortrace stack frames.

Also, document (internally) the format used by errortrace marks.