Add config file for aspell installation

component/aspell/buildout.cfg

+[buildout]
+parts =
+  aspell
+
+[aspell]
+recipe = hexagonit.recipe.cmmi
+url = http://ftp.gnu.org/gnu/aspell/aspell-0.60.6.1.tar.gz
+md5sum = e66a9c9af6a60dc46134fdacf6ce97d7

component/slapos/buildout.cfg

 [buildout]
 extends =
   ../../stack/shacache-client.cfg
+  ../aspell/buildout.cfg
   ../bison/buildout.cfg
   ../bzip2/buildout.cfg
   ../gdbm/buildout.cfg
@@ -155,4 +156,4 @@ supervisor = 3.0a12
 
 # Required by:
 # slapos.core==0.21
-zope.interface = 3.8.0
\ No newline at end of file
+zope.interface = 3.8.0