Implementation of dict comprehension

Signed-off-by: Vinzenz Feenstra <evilissimo@gmail.com>
Refactored dict and list comprehension remapping

Signed-off-by: Vinzenz Feenstra <evilissimo@gmail.com>
Added dict comprehension tests

Signed-off-by: Vinzenz Feenstra <evilissimo@gmail.com>
Ensured same output for dictcomp.py test case

Signed-off-by: Vinzenz Feenstra <evilissimo@gmail.com>
Merge pull request #65 from vinzenz/dict-comprehension

Implementation of dict comprehension