ENH: Implement feature request from issue 7885. Allow setting environment variables on a per-test basis for ctest using set_test_properties ENVIRONMENT.

BUG:  Revert 1.138.

When we install a target on Mac, we generate a call to install_name_tool to fix
install_name entries in the target for shared libraries it links.  This change
makes the step ignore entries for imported targets since their install_name
will not change and cmTarget cannot produce a mapping for them.  This fixes the
error

  GetLibraryNamesInternal called on imported target: kdelibs

seen by kde folks.

BUG: Because of Windows registry madness, we could not find the redistributables directory on Win64 builds... Add a search directory based on devenv (CMAKE_MAKE_PROGRAM) location so we can find it despite the madness.

CMAKE_MINIMUM_REQUIRED(VERSION), because the cmake they are shipped with is
always ok. Additionally, if a Find-module does CMAKE_MINIMUM_REQUIRED(), it
changes the policies as they may be set up by the project. So this shouldn't
be done in a Find-module (or surrounded by policy-push/pop commands)

Alex