support destructured params w/defaults (shorthand syntax)

[xjamundx]

While support for destructuring was added in #51 none of these cases work:

• function a({x = 10}) {}
• function a({x = 10, y: { z = 10 }}) {}
• ({x = 10}) => x
• ({x = 10, y: { z = 10 }}) => [x,y]
• [a=10] = 0
• var {a = 10} = {}

Latest spec can be found here:
estree/estree#13

[xjamundx]

Will spend like 40 minutes trying to get this to work and see what I can come up with...

[nzakas]

Cool. Just as an FYI, I'm looking at how we can potentially merge back into Esprima now that it's moving again. I won't stop you if you want to tackle this, just wanted to give to all the info before you spend more time.

[xjamundx]

That's great news, we'll see how far along I get. It's good learning :)

[xjamundx]

Related jquery/esprima#1028

[xjamundx]

Will try to take another stab at this sometime later this week...