Update README.md
Merge pull request #1 from JDWarner/fix_readme

Update README.md
FIX: pimf & zmf now behave as expected

The input `x` required indexing.
Also fixed: minor math error and redundant calculations.
Merge pull request #2 from JDWarner/fix_zmf

FIX: pimf & zmf incorrect output fixed
FEAT: Add Travis build support
FIX: Use non-implicit imports & print() to make Python 3 happy.
Merge pull request #3 from JDWarner/add_travis

FEAT: Add Travis build support