new should lower to a template function call

[Adam D. Ruppe]

Two thoughts on the subject:

1) it should probably always be inlined so it doesn't make new 
symbols in codegen.

2) the compiler should be free to cheat a little for 
optimization; if it can see the var never escapes, it might even 
still pop it on the stack (perhaps the function receives a 
pointer to the memory and if null, it is responsible for allocing 
it). This may not be implemented but the spec should at least be 
written to allow it later. This kind of optimization can be a 
real winner with scope too.