Don't print the entire declaration of the alliassee when `->toChars()` is called on an `AliasDeclaration`; just printing the name will do. This fixes #305, which otherwise tries to generate {{{ class E { void A() { alias /* recurse into E->toCBuffer() */ m; } } }}} by way of an infinite recursion (causing a segfault when the stack runs out).

static foocalled = false;
static barcalled = false;
void foo() { foocalled = true; }
void bar() { barcalled = true; }

void f(bool b)
{
  return b ? foo() : bar();
}

void main()
{
  f(true);
  assert(foocalled && !barcalled);
  f(false);
  assert(foocalled && barcalled);
}