Merge pull request #23 from jdlich/master

Fix for contains conditional
Updated dist/ builds of liquid.js
Updated split poly-fill.
Fix issue #25
Use seconds for 'date' filter

keep the same behavior as the original liquid do
Update dist
Merge pull request #26 from zjx20/master

Fix issue #25
Added more standard liquid filters
Merge pull request #27 from arcreative/standard-filters

Added more standard liquid filters
Merge branch 'master' of github.com:darthapo/liquid.js