Adds explicit alignment information for alloca instructions in general, there's a few cases that still needs to be looked at but this should catch the majority. Fixes ticket #293 .

module tangotests.switch2;

void main()
{
    int i=0;
    switch(i)
    {
    case 0:
        return;
    case 1:
        return;
    default:
        assert(0);
    }
}