Merge remote-tracking branch 'nextghost/master'

This changes the caching system to expire caches when the last modified time of
a dependency is equal to the cache file except for the meta file where the old
check is kept in order to avoid additional renderer calls and possible circular
dependencies. This avoids stale cache files but means that the parser and
renderer could now be called more than once after an edit but we currently
don't have a better fix for that.