* Fix optional chaining bug regarding spread in function calls
* Revamp optional-chain to be top down
Instead of going both upwards and downwards from the first real optional expression, we can just start from the top down.
* Add more tests
* Added optionalExpression types to babylon and babel-types
* OptionalChain transforms bug fix
* Added OptionalExpressions to babel-generator. Fixed OptionalChain Bugs
* Removed 'optionalChain' from newExpression and added test cases
* Added test cases for optionalChain
* Update index.js