Function: visible

- Added helper function to render control characters visible.  This may be
  replaced by JSON::encode.
LRParser

- Added old (non-task) parsing code, as a basis for the new parser.
- Added Tree object for parse trees.
- Added top-level entry point for testing.
Testing

- Added test script and initial grammar file.
Entity Lists

- LRParser::addEntity accumulates categorized entities for the parser.
Documentation

- Added (preliminary) example of the resultant parse tree.
Entities

- Added parser support for @entities, by merely allowing them to exist as
  terminals.
- Added sample entities.
- Extended grammar to test entities.
Arg Classifier

- Added test framework for the arg classifier (A3t).
Tree::addBranch

- Now returns a pointer to the new node, for convenience.  Throws on error.
A3t::canonicalize

- Added entity canonicalization.
Command Location

- Locateѕ, cnaonicalized and categorizes first command.
A3t::findBinary

- Locates it's own binary, and adds a 'basename' attribute.
A3t::findTerminator

- Locates and tags the terminator operator, suppressing all subsequent parsing.
  This is done early in the process, and every other step must observe the
  TERMINATOR tag.
Code Cleanup

- Removed 9 useless methods by making members public.  Accessors are nice
  sometimes, but also an unnecessary layer.
A3t::find*Override

- Locates and parses rc:<file>.
- Locates and parses rc.<name>=<value>.
- Adds a stubbed validate method to check for a sane tree.
A3t::findPattern

- Now parses patterns and extracts the pattern, which may include escaped /
  characters, which is an improvement.
Nibbler::backN

- Added a method to support multi-byte backstep through a string.
- Added unit tests.
A3t::findSubstitution

- Added support for standard and escaped '/from/to/g' constructs, which is an
  additional feature.
A3t::findTag

- Supports single-word tag add/remove, presence/absence, allowing any non-space
  character in the tag, which is an improvement.
A3t::findAttribute

- FindAttribute implemented, supporting pseudo- and uda- attribute recognition,
  which is an improvement.
- Fully parsed arguments are now locked against further parsing.
- Validation consists of looking for unlocked args.
- Added more entities for testing.
- Updated test script.
Tree::unTag

- Added a method for removing a tag.