Add Standard Markdown testsuite.

You could run the Parsedown testsuite only with:
    phpunit --testsuite ParsedownTests

And you could run the Standard Markdown one with:
    phpunit --testsuite StandardMarkdown

See more at http://standardmarkdown.com/
Add Docblock and attribution to JS test runner
Merge pull request #217 from hkdobrev/standard-markdown

Standard markdown
Rename Standard Markdown to CommonMark

http://blog.codinghorror.com/standard-markdown-is-now-common-markdown/

https://github.com/coding-horror/coding-horror.github.io/commit/2d37920c39d15db0769f710bd2414e9a2ed7b565
Merge pull request #218 from hkdobrev/common-mark

Rename Standard Markdown to CommonMark
Rename everything to CommonMark
Merge pull request #221 from hkdobrev/commonmark-renaming

Rename everything to CommonMark
Merge branch 'master' into commonmark
simplify
improve consistency
simplify
markup formatting shouldn't impact results
improve output readability
Merge remote-tracking branch 'origin/commonmark'

Conflicts:
	Parsedown.php
	phpunit.xml.dist
	test/ParsedownTest.php
improve CommonMark compliance
update test
improve extensibility
Merge branch 'master' of https://github.com/erusev/parsedown