Added lexer/renderer stubs
atx headers + access to named rules via lexers
lhead, fences, indent cache
Updated test fixtures & loader
Splitted block lexer & index to files
Added blockquotes stub
Improved fixtures structure
Added bullet list stub

This is incomplete yet:

 - one element per list only
 - list item may contain only one paragraph
Fixed fenses & updated tests
Implemented nested blocks lexing, now block quotes works as expected
replaced jshint with eslint for better style check
Renderer rules are now modifiable
Added lists and basic support for tables
list review & reorganize
Moved empty lines logic from rules to block parser
Added stmd spec processor tool
Minor assorted fixes to better match spec
Pass token index to renderer fn + use it for br magick
Replaced old stmd tests with fresh specs
Tight lists + shink start of strings in inline blocks