Revert Remove WindowLevelInterface.tcl and WindowLevelInterface.py

Signed-off-by: Andrew Maclean <andrew.amaclean@gmail.com>

Change-Id: If5476fc12ab14779614d03dfdeea191b478a8029
Merge topic 'delete-WindowLevelInterface' into master

50ea2323 Revert Remove WindowLevelInterface.tcl and WindowLevelInterface.py