Removed AL_usdmaya_ProxyShapeSelect command and related functionality

[jonjondev]

In response to the closure of PR #1855 and the flagged changes of discussion item #1879, this PR removes the AL_usdmaya_ProxyShapeSelect command from the AL plugin, which should be handled from this point forwards via UFE selection.

Several tests have been rewritten to accommodate the changes, and a number of custom transform tests previously used the command to build transform chains as test data for convenience. This shift marks version 3 for the AL plugin.

[kxl-adsk]

@fabal, @J-Mo63 The PF looks to be failing because of two errors (one platform-dependent and one Maya version dependent):

15:48:51     /local/S/jenkins/workspace/ecg-mayausd-branch-preflight-python3-osx/ecg-maya-usd/maya-usd/plugin/al/lib/AL_USDMaya/AL/usdmaya/nodes/ProxyShapeSelection.cpp:45:13: error: unused function 'addObjToSelectionList' [-Werror,-Wunused-function]
15:48:51     inline void addObjToSelectionList(MSelectionList& list, const MObject& object)

and because of

15:45:44     S:\jenkins\workspace\ecg-mayausd-branch-preflight-2019-no-ufe-windows\ecg-maya-usd\maya-usd\plugin\al\plugin\AL_USDMayaTestPlugin\AL\usdmaya\nodes\test_TransformMatrix.cpp(24): fatal error C1083: Cannot open include file: 'mayaUsd/ufe/Utils.h': No such file or directory

both errors are available in logs associated with PF.

[jonjondev]

@fabal, @J-Mo63 The PF looks to be failing because of two errors (one platform-dependent and one Maya version dependent):

15:48:51     /local/S/jenkins/workspace/ecg-mayausd-branch-preflight-python3-osx/ecg-maya-usd/maya-usd/plugin/al/lib/AL_USDMaya/AL/usdmaya/nodes/ProxyShapeSelection.cpp:45:13: error: unused function 'addObjToSelectionList' [-Werror,-Wunused-function]
15:48:51     inline void addObjToSelectionList(MSelectionList& list, const MObject& object)

and because of

15:45:44     S:\jenkins\workspace\ecg-mayausd-branch-preflight-2019-no-ufe-windows\ecg-maya-usd\maya-usd\plugin\al\plugin\AL_USDMayaTestPlugin\AL\usdmaya\nodes\test_TransformMatrix.cpp(24): fatal error C1083: Cannot open include file: 'mayaUsd/ufe/Utils.h': No such file or directory

both errors are available in logs associated with PF.

Yup seen that warning and the UFE issue. We have a fix ready for those and hopefully it'll be up soon.