Remove top-level 'var' and 'import' directories that seem to be a legacy

from the before-the-"skel"-directory times. Move things that we might want to
keep to "skel" instead.
Make sure we remove everything that comes out of an inplace instance ("make instance").

import/README.txt

-This directory is used by the running Zope process to import objects
-into the ZODB.  Please place any files that you wish to be able to
-import into this directy.  For more information, please see The Zope
-Book.

inst/Makefile.in

@@ -67,6 +67,7 @@ instance: build
 uninstance:
 	${RMRF} "${BASE_DIR}/bin"
 	${RMRF} "${BASE_DIR}/etc"
+	${RMRF} "${BASE_DIR}/import"
 	${RMRF} "${BASE_DIR}/log"
 	${RMRF} "${BASE_DIR}/var"
 	${RMRF} "${BASE_DIR}/Products"