Remove usage of CMAKE_CURRENT_LIST_DIR now that we have CMP0017

This puts the new search behaviour for included files in action, i.e.
now when a file from Modules/ include()s another file, it also gets the
one from Modules/ included, i.e. the one it expects.

Alex

Modules/FindGnuplot.cmake

@@ -34,7 +34,7 @@ SET(GNUPLOT ${GNUPLOT_EXECUTABLE})
 
 # handle the QUIETLY and REQUIRED arguments and set GNUPLOT_FOUND to TRUE if 
 # all listed variables are TRUE
-INCLUDE("${CMAKE_CURRENT_LIST_DIR}/FindPackageHandleStandardArgs.cmake")
+INCLUDE(FindPackageHandleStandardArgs)
 FIND_PACKAGE_HANDLE_STANDARD_ARGS(Gnuplot DEFAULT_MSG GNUPLOT_EXECUTABLE)
 
 MARK_AS_ADVANCED( GNUPLOT_EXECUTABLE )