Added 'matrix' method, and change the ! method to
use define_method.
Adding yard comments for all methods
Fixed bugs, make the original method saved in
class variable in a hash.
Remove yardoc from git and upgrade version.
Version 0.0.5:
~ Change class methods: `experience' and `remember' into
  `know' and `recall', respectively.
~ Change default value of all `columns' argument to 72
~ Remove instance variables: `@rows' and `@columns'