Add DocString parsing capability

Thank to @rwestgeest for pairing with me!
Remove uneccesary detail
Use GherkinBuilder for creating test data
Create README.md with travis link
Create .travis.yml
Create Gemfile. That should make Travis' rake run happier since it should make gems available.
Refactor, moving code into new Core::Parser
Refactor parser spec
Ignore Gemfile.lock
Fix require paths
Add encoding header for 1.9
More encoding fixes for old rubies
rbenv wants exact ruby version
added parsing data table argument in step

we had to remove the diff! and to_s(...) methods on Ast::Table because they had a
dependency on the pretty formatter.
Merge pull request #4 from rwestgeest/master

Add parsing data table argument in step parsing
Basic parsing of scenario outlines

There's going to be stuff missing (e.g. the location of the example
rows) but we can add that later.
Rename Parser to GherkinParser
move spec/GherkinBuiler into core namespace
Add bundler and explain gitignore
Move test things into Test:: namespace