Previously we saw a bug that when we have nested if statements
and an alternate then the generated code may confuse which
if statement the alternate belongs to.
e.g.
```
if (foo) if (bar) bar(); else baz();
```
But this was handled by looking at the consequent
and if it's an if we add a block. However we didn't
handle situations where it's not an if but the last
recursive statement is an if:
```
if (foo) while (bar) if (baz) baz(); else shoosh()
```
This handles it by recurring until we get the last
statement.
I'm extremely stupid and didn't commit as I go. To anyone reading this
I'm extremely sorry. A lot of these changes are very broad and I plan on
releasing Babel 6.0.0 today live on stage at Ember Camp London so I'm
afraid I couldn't wait. If you're ever in London I'll buy you a beer
(or assorted beverage!) to make up for it, also I'll kiss your feet and
give you a back massage, maybe.
