MarkdownLoader uses GFM
Merge branch 'master' into 34-linebreak

Conflicts:
	lib/ataru/markdown_loader.rb
	lib/ataru/traverser.rb
	test/traverser_test.rb
added input type, gfm, to all test cases
Merge pull request #41 from CodePadawans/34-linebreak

MarkdownLoader uses GFM