0.5.0

Due to changes to permutation_entropy this release might break compatibility with previous versions.

This release introduces improvements to permutation_entropy (thanks @raphaelvallat)

• Changed signature of the def permutation_entropy(time_series, m, delay) to def permutation_entropy(time_series, order=3, delay=1, normalize=False)
• Increased speed of the permutation_entropy
• Changed the log base from 10 to 2 in permutation_entropy (as per Band and Pompe 2002)
• Added normalization to the permutation_entropy
• Default value for the permutation_entropy are changed
• More tests
• Cleanup of docs with PEP8 and NumpyDoc