Add some experimental new monomorphic type conversion operators.
Add some experimental new monomorphic type conversion operators.

diku-dk/futhark,ihc/futhark,HIPERFIT/futhark,HIPERFIT/futhark,HIPERFIT/futhark,diku-dk/futhark,ihc/futhark,diku-dk/futhark,ihc/futhark,diku-dk/futhark,diku-dk/futhark