This converts the KWSys license to a pure 3-clause OSI-approved BSD
License.  We drop the previous license clause requiring modified
versions to be plainly marked.  We also update the KWSys copyright to
cover the full development time range.

Fix for Bug #9190, -U did not work on case insensitive file systems because of call to glob convert to regex that expected to work with files.

ENH: Improve FILE GLOB_RECURSE handling of symlinks with a new CMake policy. CMP0009 establishes NEW default behavior of not recursing through symlinks. OLD default behavior or explicit FOLLOW_SYMLINKS argument to FILE GLOB_RECURSE will still recurse through symlinks.

ENH: Add RecurseThroughSymlinks data member to kwsys::Glob. Allows recursive globs to skip symlinks when necessary. Default to true for backwards compatible behavior. Used from the ctest coverage handler to avoid recursing through the '/Applications' directory on the Mac looking for *.da files... Should fix the hangs reported recently by Mac CMake dashboard submitters.

ENH: Exposed pattern->regex API.  Cleaned up and commented implementation of pattern->regex conversion.