- Implemented RegX class to maintain a separate compile, and match
method, thereby allowing efficient re-use of the regex. This is
critical to Expression::eval, where an identical regex might be
applied to every task.
- Obsoleted rx.{h,cpp}, which combined the compile and match steps
into a single call, and is therefore not efficient when used in
the context of filtering.
- Fixed some unit tests that weren't building. Now they do. They
don't work of course (don't be silly) but that's a problem for
another day.
- Modified all code that relies on rx.h to use RegX.h.
