Regex

- 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.

test/CMakeLists.txt

@@ -7,9 +7,9 @@ include_directories (${CMAKE_SOURCE_DIR}
                      ${TASK_INCLUDE_DIRS})
 
 set (test_SRCS arguments.t att.t autocomplete.t color.t config.t date.t
-               directory.t dom.t duration.t file.t filt.t i18n.t json.t lexer.t
-               list.t nibbler.t path.t record.t rx.t seq.t t.benchmark.t t.t
-               taskmod.t tdb.t tdb2.t text.t uri.t util.t variant.t view.t
+               directory.t dom.t duration.t file.t i18n.t json.t lexer.t list.t
+               nibbler.t path.t record.t rx.t t.benchmark.t t.t taskmod.t tdb.t
+               tdb2.t text.t uri.t util.t variant.t view.t
                json_test)
 
 add_custom_target (test ./run_all DEPENDS ${test_SRCS}