21/1/2010 version 0.4.0
* added command API
* added many new commands, i.e ls_methods and friends
* modified other commands
* now accepts greater customization, can modify: input, output, hooks,
	prompt, print object
* added tab completion (even completes commands)
* added extensive tests
* added examples
* many more changes
9/12/2010 version 0.1.3
* Got rid of rubygems dependency, refactored some code.
8/12/2010 version 0.1.2
* now rescuing SyntaxError as well as Racc::Parser error in valid_expression?
8/12/2010 version 0.1.0
* release!