implemented tables
resolved issue with escaped pipes
corrected some omitted characters needing escape in _split_on_unescaped
added tolerance for up to three spaces for headers and first horizontal rule as per markdown extra
added some tests for tables
added reference to new tests
multimarkdown-style tables, with continuations, row spanning cells
header cells, and optional borders
Merge branch 'tables' of https://github.com/redsun82/markdown-js into advanced_tables
Merged branch 'advanced_tables' of https://github.com/redsun82/markdown-js

Conflicts:
	lib/markdown.js