ENH: Add Multi-sampling option

This commits leverage the functionality already added in CTK [1] by
adding "Views" settings panel allowing to enable/disable
anti-aliasing.

[1] https://github.com/commontk/CTK/commit/b39d95edd9be0965a85bcd9fbc12bb64edb9041a

From: Eric Larson <larson.eric.d@gmail.com>

git-svn-id: http://svn.slicer.org/Slicer4/trunk@23305 3bd1e089-480b-0410-8dfb-8563597acbee
ENH: N4ITKBiasFieldCorrection: Restore original default for iteration number.

This commit reverts the change added as part r21845 to resolve issue #3034

To be compatible with code expecting the original default value, the value
is changed back to to "50,40,30".

From: Andrey Fedorov <fedorov@bwh.harvard.edu>

git-svn-id: http://svn.slicer.org/Slicer4/trunk@23306 3bd1e089-480b-0410-8dfb-8563597acbee