Made LessFilter compatible with Less v2
Made LessFilter compatible with Less v2

lenar/assetic,shandy05/assetic,renaatdemuynck/assetic,lellimecnar/assetic,lenar/assetic,lellimecnar/assetic,lenar/assetic,shandy05/assetic,lenar/assetic,shandy05/assetic,Sgoettschkes/assetic,kriswallsmith/assetic,renaatdemuynck/assetic,matthiasmullie/assetic,Sgoettschkes/assetic,matthiasmullie/assetic,lellimecnar/assetic,shandy05/assetic,matthiasmullie/assetic,kriswallsmith/assetic,lellimecnar/assetic,Sgoettschkes/assetic,kriswallsmith/assetic,kriswallsmith/assetic,renaatdemuynck/assetic,Sgoettschkes/assetic,matthiasmullie/assetic,renaatdemuynck/assetic