Deprecate extract! calling private methods

Fix #140
There's no Object#public_send in 1.8 and AS :(
Add array of partials rendering
Add README about collection partial rendering

Closes #133
Some README fixes
Another tiny README fix [ci skip]
Version 1.5.0
Add link to AMS to README [ci skip]
Add Coveralls
add info about caching to readme
Merge pull request #141 from pitr/patch-1

add info about caching to readme
update from upstream