Add tests for LessphpFilter's 'formatter'.
Add tests for LessphpFilter's 'formatter'.

https://github.com/amyboyd/assetic/commit/180c7dbe3b1a1a78348188682b76cf3d479f5320
fredemmott/assetic,lenar/assetic,fredemmott/assetic,shandy05/assetic,mubassirhayat/assetic,Sgoettschkes/assetic,Sgoettschkes/assetic,lenar/assetic,sportradar/assetic,kriswallsmith/assetic,matthiasmullie/assetic,lellimecnar/assetic,matthiasmullie/assetic,Sgoettschkes/assetic,fredemmott/assetic,lellimecnar/assetic,mubassirhayat/assetic,kriswallsmith/assetic,mubassirhayat/assetic,Sgoettschkes/assetic,shandy05/assetic,renaatdemuynck/assetic,lenar/assetic,sportradar/assetic,matthiasmullie/assetic,webmozart/assetic,renaatdemuynck/assetic,webmozart/assetic,renaatdemuynck/assetic,kriswallsmith/assetic,shandy05/assetic,lellimecnar/assetic,shandy05/assetic,renaatdemuynck/assetic,matthiasmullie/assetic,webmozart/assetic,kriswallsmith/assetic,lellimecnar/assetic,lenar/assetic,sportradar/assetic