Regexes

- Added regex support to substirutions.
- Fixed bug that prevented 1.9.4 from shipping with regexes.  If the
  description is "aXXaaXXa", and the substitution is /XX/.../ then the
  first substitutions changes the length of the string to "a...aaXXa"
  and therefore invalidates the index for the second match, and makes
  this change: "a...a...Xa".  The fix is to keep a running 'skew' count
  of the difference in 'from' and 'to' length, to adjust the match
  indexes.
- Moved the helper deltaSubstitutions function into the Task object,
  which makes more sense.
- Cleaned up output composition for CmdAdd.
- Eliminated #ifdef FEATURE_REGEX.  They are here to stay.

src/main.h

@@ -29,8 +29,6 @@
 #define L10N                                           // Localization complete.
 
 #define FEATURE_NEW_ID       1   // Echoes back new id.
-//#define FEATURE_REGEX        1   // Enables regexes for attribute modifiers,
-//                                 // subst, general search.
 
 #include <string>
 #include <vector>
@@ -59,7 +57,6 @@ int deltaPrepend (Task&);
 int deltaDescription (Task&);
 int deltaTags (Task&);
 int deltaAttributes (Task&);
-int deltaSubstitutions (Task&);
 
 // rules.cpp
 void initializeColorRules ();