Added IrTypeFunction and IrTypeDelegate and eliminated IrDType. This means the Type::ir field can be removed. It's the final part needed for the move to a slightly more sane type system. Now the whole thing just needs to be cleaned up :P Added -v-cg switch, which right now just prints "codegen: module.name (module/name.d)" to stdout, this can really help figuring out where, in some complex build command, things go wrong.

[Environment] 
DFLAGS=-I@RUNTIME_DIR@ -I@RUNTIME_DIR@/lib/common -L-L%@P%/../lib -d-version=Tango -defaultlib=@RUNTIME_AIO@ -debuglib=@RUNTIME_AIO@