better error handling in Sass extension functions
better error handling in Sass extension functions

briangonzalez/susy,webdev1001/susy,kraftner/susy,ericam/susy,bradgessler/compass-susy-plugin,MichaelArestad/susy,jinzhu/susy,Snugug/susy,kaij/susy,pairyo/susy,gabskoro/susy,jinzhu/susy,rajkaushik05/susy,greyhwndz/susy,gastonfig/susy,BionicClick/susy,acdlite/susy,Sapphire64/susy,gonsakon/susy,rajkaushik05/susy,ericam/susy,oddbird/susy,rainforestapp/susy,Sapphire64/susy,essdot/susy,katoffsky/susy,BionicClick/susy,tsi/susy,ericam/susy,kaij/susy,kraftner/susy,webdev1001/susy,bangpound/compass-susy-plugin,katoffsky/susy,oddbird/susy,greyhwndz/susy,leopic/susy,gastonfig/susy,gonsakon/susy,greyhwndz/susy,tbredin/susy,kaij/susy,leopic/susy,pairyo/susy,MichaelArestad/susy,gabskoro/susy,Sapphire64/susy,gabskoro/susy,pairyo/susy,tsi/susy,justnorris/susy,dgoodlad/compass-susy-plugin,lencioni/susy,briangonzalez/susy,rainforestapp/susy,katoffsky/susy,essdot/susy,rainforestapp/susy,justnorris/susy,lencioni/susy,kraftner/susy,BionicClick/susy,acdlite/susy,rajkaushik05/susy,tbredin/susy