REWORD API Revamp (See http://issue.cc/r3/1990)

Requested changes (by requester):
* Binary support, and working tag support (BrianH)
* `/case` for case-sensitive comparison (BrianH)
* Specifying leading and trailing delimiters with `/escape` (i.e. for HTML/XML entities) (BrianH)
* Being able to specify `none` as an `/escape`, equivalent to `""` now (HostileFork)
* Evaluating value expressions directly in a block spec, rather than requiring the spec to be reduced, and `/only` to turn that off (rgchris, BrianH, prompted by GrahamChiu's RebolBot code)
* Evaluating block values as code like functions, to cut down on function creation overhead, and `/only` to turn that off (rgchris)
* Special-case treatment of set-word keys as if they were regular words, so block and object specs can be compatible (BrianH)
* Special-case treatment of lit-word keys as if they were regular words, to be compatible with fully reduced specs (BrianH)
* Directly using values specs that already match what we need internally, to save overhead (BrianH)
* Better-phrased doc strings that are short enough to not wrap on the Windows console (BrianH)

See http://issue.cc/r3/1990 for the example code.