Moving ode45, odeset, odeget, and levenshtein from odepkg to core. * libinterp/corefcn/levenshtein.cc: move function from odepkg into core * libinterp/corefcn/module.mk: include levenshtein.cc * scripts/ode: move ode45, odeset, odeget, and all dependencies from odepkg into core * scripts/module.mk: include them * doc/interpreter/diffeq.txi: add documentation for ode45, odeset, odeget * NEWS: announce functions included with this changeset * scripts/help/__unimplemented__.m: removed new functions

--- a/NEWS
+++ b/NEWS
@@ -43,6 +43,9 @@
  ** Other new functions added in 4.2:
 
       psi
+      odeset
+      odeget
+      ode45
 
  ** Deprecated functions.