Wrap zip() calls in list() to preserve Python 2 semantics
Wrap map() calls in list() to preserve Python 2 semantics

Closes gh-53
Fix tests for map fixer
Preserve Python 2 semantics by wrapping calls to filter() in list()
Merge pull request #55 from takluyver/zip-map-list-wrap

Preserve Python 2 semantics for zip(), map(), and filter()