Redundant calculations slowing down performance

[MatthewScholefield]

After reverting this PR the performance suffers due to redundant calculations. For the time being, I plan on uploading a fork with the change to PyPI so that it can be included in other projects via setup.py.

[astorfi]

@MatthewScholefield The pull request broke some part of the package so I had to remove it temporarily. I am not quite sure about your point to upload another fork to PyPI. You mean related to SpeechPy?
This pull request is not compatible with the whole package structure. It needs further investigation.
Please feel free to have your own work but regarding the upload to PyPI or other kinds of independent upload please make sure to LICENSE file.

About being included in other projects via setup.py, I am not quite sure if I got the difference.
Please send me your feedback.

[MatthewScholefield]

What do you mean exactly by not being compatible? Are you referring to an import error when run in Python 2? Let me know if this PR looks any better.