[libigtl/f19] (3 commits) ...Install cmake support files in _libdir not _datadir

[mrceresa]

Summary of changes:

  8ed82c3... Move cmake files to modules dir (*)
  1968d47... Fixed wrong dir in devel package (*)
  cb14fc7... Install cmake support files in _libdir not _datadir (*)

(*) This commit already existed in another branch; no separate mail sent