[upstream PR #263] Integration blocked: Feature/support masked array

[GeorgePearse]

Upstream PR: rlabbe/filterpy#263
Issue Type: Cherry-pick failed: fatal: bad object 3a72d8b28bde787d33a6f7704213919b508df358

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Problem

Error: Cherry-pick failed: fatal: bad object 3a72d8b28bde787d33a6f7704213919b508df358

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Original Description

Linked with issue #236

Add support for numpy masked array for measurement used in update methods and functions. This allow using masked array in batch_filter instead of list with None.

Unit tests have been updated and a working example can be found here:

• https://github.com/antoinecollet5/kalman-filtering/blob/develop/linear_case_filterpy.ipynb