added some tests and fixed small bugs
added command line script
added basic description to README

issue #17
Update README.md
added PHP 5.6 to unit tests
do not break paragraph on different block markers by default
allow html comments
better tabulator support for lists
consistency for HRs
improved link and reference parsing
improved inline html handling
added more tests ported from original markdown implementation

source:
http://daringfireball.net/projects/downloads/MarkdownTest_1.0.zip
finally have all tests of the orinal markdown parser passing
added code coverage via scrutinizer
added banners to readme
added back php import for scrutinizer
Merge branch 'master' into list-items-undef-ref

* master:
  added back php import for scrutinizer
  added banners to readme
  added code coverage via scrutinizer
  finally have all tests of the orinal markdown parser passing
  added more tests ported from original markdown implementation
  improved inline html handling
  improved link and reference parsing
  consistency for HRs
  better tabulator support for lists
  allow html comments
  do not break paragraph on different block markers by default
  added PHP 5.6 to unit tests
  Update README.md
  added basic description to README
  added command line script
  added some tests and fixed small bugs
fixed link and reference parsing to support more sophisticated cases

e.g. nested brackets like [[hi there [this is a
link]]](http://www.cebe.cc)