php cache method works better with large projects
reduce calls to is_method
foreach() in to-css-visitor
use object_ids instead of recursive inInheritanceChain()
$parents property not needed
only run extendsVisitor if less has extends
add common strings to environment
make firstSelector a static variable
correct string values
property_exists() not needed in visitRuleset
property_exists() not needed in makeImportant()
property_exists() not needed in Ruleset->genCSS()
check for Expression object instead of using property_exists
too many calls to releaseMemory()
set lastRule by default
set importMultiple default
count() not needed
count() not needed to check $strs
remove unecessary count() and property_exists() calls in toCSSVisitor
use foreach in Selector->compile()