Refactored EventWindow to use a numpy array under the hood.
Changed testcase to use an object based EventWindow.
Updates to pass flake8 tests.
Updated doc.
Removed some deprecated methods from DataSeries (appendValue, appendValueWithDatetime, getValue, getValues, getValuesAbsolute).
Removed getFirstValidPos and getLength from DataSeries interface.
Added resize support.
Working on numpy.array based DataSeries.
Removed dead code.
Merge branch 'numpy-refactoring'