Refactor code parser to ast from regex

[roypeled]

The regex parsing engine was not handling compiled code correctly, it would extract malformed tokens when self invoked functions and compiled imported modules were introduced in the code ((0, imported)(arg)).

I used babel's parser to parse the code string and traversed the AST to extract functions and method names.

Several other changes had to be made, since the Regex parser did not rely on valid code, it could handle parts of complete code to extract information.
This is no longer valid, so I had to change the way ObjectPropertyCodeRetriever works:
It used to get object and property, and extract the code for that property. Since the only usage was when iterating over an object's fields, and only the functions were necessary, I changed it to return a functional mock class with all the required properties.
I changed the tests to match this scenario.

[LironHazan]

@roypeled Thanks that's a great contribution and the way to go IMO, we had an older thread about the need of having a parser.

[LironHazan]

LGTM

[roypeled]

Hey @cspotcode, just wanted to get your input before we merge and publish a new version with the babel parser!