Merge topic 'rename-cmProp-in-cmValue'

59ad7a1c24 Move helpers functions from cmStringAlgorithms.h to cmValue.h
edf67dd039 cmValue: add IsInternallyOn methods
cc56dc7468 Rename cmProp in cmValue

Acked-by: Kitware Robot <kwrobot@kitware.com>
Tested-by: buildbot <buildbot@kitware.com>
Merge-request: !6554