Add missing function integral.m (bug #42037). * integral.m: New function file, primarily a wrapper to quadgk or quadv. * /scripts/general/module.mk: Add integral.m to build system. * quad.txi: Add doc reference to integral after description of quad functions. * NEWS: Annouce new function integral. * __unimplemented__.m: Remove integral from the list.

--- a/scripts/general/module.mk	Sun Sep 17 15:53:49 2017 -0400
+++ b/scripts/general/module.mk	Tue Sep 05 11:25:21 2017 -0400
@@ -41,6 +41,7 @@
   %reldir%/idivide.m \
   %reldir%/inputParser.m \
   %reldir%/int2str.m \
+  %reldir%/integral.m \
   %reldir%/interp1.m \
   %reldir%/interp2.m \
   %reldir%/interp3.m \