Adding test for Composite transform AddTransform method.
Adding test for Composite transform AddTransform method.

The AddTransform method currently returns Self and should return
nothing.

Change-Id: I8fd061cec95bc11ea4b528390320a9b521b917c4

SimpleITK/SimpleITK,InsightSoftwareConsortium/SimpleITK,blowekamp/SimpleITK,InsightSoftwareConsortium/SimpleITK,InsightSoftwareConsortium/SimpleITK,richardbeare/SimpleITK,InsightSoftwareConsortium/SimpleITK,kaspermarstal/SimpleElastix,blowekamp/SimpleITK,kaspermarstal/SimpleElastix,SimpleITK/SimpleITK,SimpleITK/SimpleITK,blowekamp/SimpleITK,richardbeare/SimpleITK,kaspermarstal/SimpleElastix,blowekamp/SimpleITK,InsightSoftwareConsortium/SimpleITK,blowekamp/SimpleITK,richardbeare/SimpleITK,InsightSoftwareConsortium/SimpleITK,kaspermarstal/SimpleElastix,richardbeare/SimpleITK,richardbeare/SimpleITK,blowekamp/SimpleITK,InsightSoftwareConsortium/SimpleITK,SimpleITK/SimpleITK,richardbeare/SimpleITK,kaspermarstal/SimpleElastix,richardbeare/SimpleITK,SimpleITK/SimpleITK,blowekamp/SimpleITK,SimpleITK/SimpleITK,richardbeare/SimpleITK,kaspermarstal/SimpleElastix,SimpleITK/SimpleITK,blowekamp/SimpleITK,kaspermarstal/SimpleElastix,InsightSoftwareConsortium/SimpleITK,SimpleITK/SimpleITK