the typefunction branch is now only fails expected test

[Stefan Koch]

Good evening,

I am proud to say that after a couple minutes of bugfixing.

the latest typefunction development branch 'talias_master' does 
no longer fail any tests which don't have to do with the semantic 
changes

the tests which it fails are:

---
/*
TEST_OUTPUT:
---
fail_compilation/fail239.d(8): Error: type `F` is not an 
expression
---
*/
class F { int x; }
alias typeof(F).x b;
---

/*
TEST_OUTPUT:
---
fail_compilation/fail240.d(9): Error: type `F` is not an 
expression
---
*/

class F { int x; }
alias typeof(typeof(F).x) b;
---

and

---
/*
TEST_OUTPUT:
---
fail_compilation/fail248.d(9): Error: type `int` is not an 
expression
---
*/

alias int foo;
typeof(foo) a; // ok
---

Because a type is now indeed an expression.
And the type of 'int' is '__type__'

It should also be noted that, with a minor change to phobos in 
'CommonType' it's unittests pass.
The reason why CommonType has to be changed is because it is 
written to assume that typeof(some_type) yields an error.
Which is now no longer the case.

apart from that; Everything that used to work works!

When using type functions with std.range  however things are 
still failing since std.range is written in an obtuse style and 
very brittle.

Cheers,

Stefan