comment some stuff
fix esi/ajax in piped requests

thanks to @mwisner
change some passed requests to pipe, removed cache hit ttl extension
make warm-cache script handle xpath options better and use multiple processes
update changelog
use more secure hash method
add advanced session validation
add changelog note
fix missing messages block methods
add note to readme about 1.5 compat
update how-it-works section for ajax stuff
Merge branch 'devel'

Conflicts:
	README.md
bump version to 0.3.2