Fix Matches method for FD values.

This would cause most attempted matches on FD values to fail,
and could also potentially cause matches to succeed when they
should not.
Fix comments, range matching is only for dates and times.
More case folding, georgian and a few symbols.

The important ones are the symbols for Ohm, Kelvin, and Angstrom
because they have equivalent characters elsewhere.
Improve comments on case folding of Greek.
Fix segfault when using Matches on binary values.

Under certain circumstances, the recent change to CompareEach
caused a segfault.