R-values and const ref

[Eldar Insafutdinov]

A while back dmd stopped allowing rvalues as ref function arguments. I
entirely understand why it was done, but the same restriction applies to the
ref const function parameters. This causes a lot of pain and at the moment
makes me use pass-by-value parameters(most notably when using structs). C++
doesn't have any problem with const ref and rvalues. Can we please restore
this behavior for const ref?