[svn r330] Implemented synchronized statements. Changed the tryfinally handlers to a more generalized EnclosingHandler. Changed ClassInfoS to be mutable so they can be used as locks. Added new BB after throw ala return/break etc.

module tangotests.mem2;

void main()
{
    int* ip = new int;
    assert(*ip == 0);
    *ip = 4;
    assert(*ip == 4);
    delete ip;
    assert(ip is null);
}