comment out unused lexer types
add source map link to homepage
update contributing.md with make tasks
allow {% end[tag] tokens... %}. fixes gh-278
allow parent to work in middle parent templates

Ensures all parents build the full token list necessary for rendering itself in the chain.

Fixes gh-277
start examples for custom tags
update still package
add poperties to member, lexer to tags for custom tag docs
add special parser callback types
move custom tags docs to new extending page
pave way for custom filters in extending page
Merge branch 'docs/custom-tags' of github.com:paularmstrong/swig into docs/custom-tags

Conflicts:
	Makefile
	docs/docs/tags.html