add tests for max and maxmin project
fix bug in subsample dims calc, add subsample test
add tests for images filter methods and planes
fix and add test for images subtract method
Merge branch 'master' into image_tests to get new series stats methods
add tests for seriesMedian and seriesPercentile, remove unused 'interpolation' param
add series maxProject test
Merge pull request #70 from industrial-sloth/image_tests

new Images and Series unit tests