ENH: Implement RollingBallSubtractBackground filter

Change-Id: I532113fb3be2b4b30bd60d4f51737f88bb55a91c
STYLE: Remove unused commented-out code

Change-Id: Ib9814d89e841faca47ec4ed8cae3ad274ff2f75d
STYLE: Rename RollingBallStructuringElement to GrayscaleBallStructuringElement

Change-Id: Ifa6c6adfea10fd212ac5c1b2ade6fc2c60afd593
COMP: Fix linking issues in Windows

Change-Id: Ieb3935e968b15dbd7975000c0ed5ca4f4fdb7752
COMP: Fix up the CMake tests and move the images to Midas server

Change-Id: I89637852b601f2a316a049243e82a4bd3a5a0800