Implement else if control flow

[danobi]

Before, you could do:

if (<cond>)
{
    <stmt>
}
else
{
  if (<cond2>)
  {
    <stmt2>
  }
}

Now, you can do:

if (<cond>)
{
    <stmt>
}
else if (<cond2>)
{
    <stmt2>
}

This makes things more natural for programmers coming from C-ish
languages.