Add permutation module
autopep8 formatting
Turned new permutation variant by shixing into meta-hash to keep Engine minimal
Uncommented tests
Merged new permutation component
Added requirements
Fixed issue with default memory storage on all engines that was shared
Added HashPermutationMapper, another variant

that permutates binary bucket keys and holds a dictionary for mapping
bucket keys to lists of bucket keys.
Merged develop and master
Merge remote-tracking branch 'upstream/master'