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).

module throw1;

extern(C) int rand();

class C
{
}

void func(bool b)
{
    if (b)
        throw new C;
}

int main()
{
    bool b = true;
    try
    {
        func(b);
    }
    catch(Object)
    {
        return 0;
    }
    return 1;
}