Greeb 0.2.4

The release 0.2.4 of Greeb introduces spelling corrections in README.md. The only significant code change in this version is relocation of the Tokenizer.step method into Tokenizer.tokenize.

Happy New 2014 Year

This release incorporates many improvements in documentation, command-line interface and also introduces a few hopefully useful features including Span#slice and Parser.apostrophes. This is the first release of Greeb in 2014.