* avoid duplicating impure initializers in object rest destructuring
* reuse existing VariableDeclarations in object rest destructuring, to fix two issues:
1. inserting an additional VariableDeclaration after the current one may change order of operations, which is unsafe if a future VariableDeclarator refers to a destructured variable.
2. The entire VariableDeclaration is removed when all properties are rest properties, indiscriminately removing other variables
* object rest - fix when destructuring in variables/parameters
* fixes + ExportNamedDeclaration support
* Account for CatchClause
* support ForXStatement
* support assignment expression? + PR fixes
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.