doc: Shorten some long subsection names in Manual. Remove excess spaces from ends of @menu definitions. * doc/interpreter/arith.txi, doc/interpreter/basics.txi, doc/interpreter/bugs.txi, doc/interpreter/container.txi, doc/interpreter/data.txi, doc/interpreter/diagperm.txi, doc/interpreter/diffeq.txi, doc/interpreter/emacs.txi, doc/interpreter/expr.txi, doc/interpreter/external.txi, doc/interpreter/func.txi, doc/interpreter/grammar.txi, doc/interpreter/gui.txi, doc/interpreter/install.txi, doc/interpreter/intro.txi, doc/interpreter/io.txi, doc/interpreter/java.txi, doc/interpreter/linalg.txi, doc/interpreter/matrix.txi, doc/interpreter/nonlin.txi, doc/interpreter/numbers.txi, doc/interpreter/octave.texi, doc/interpreter/optim.txi, doc/interpreter/plot.txi, doc/interpreter/preface.txi, doc/interpreter/quad.txi, doc/interpreter/sparse.txi, doc/interpreter/stats.txi, doc/interpreter/stmt.txi, doc/interpreter/strings.txi, doc/interpreter/system.txi, doc/interpreter/var.txi: Shorten some long subsection names in Manual. Remove excess spaces from ends of @menu definitions.

--- a/doc/interpreter/system.txi	Fri Aug 02 15:16:48 2013 -0400
+++ b/doc/interpreter/system.txi	Fri Aug 02 13:52:39 2013 -0700
@@ -26,17 +26,17 @@
 and even start other programs from the Octave prompt.
 
 @menu
-* Timing Utilities::            
-* Filesystem Utilities::        
+* Timing Utilities::
+* Filesystem Utilities::
 * File Archiving Utilities::
 * Networking Utilities::
-* Controlling Subprocesses::    
-* Process ID Information::      
-* Environment Variables::       
-* Current Working Directory::   
-* Password Database Functions::  
-* Group Database Functions::    
-* System Information::          
+* Controlling Subprocesses::
+* Process ID Information::
+* Environment Variables::
+* Current Working Directory::
+* Password Database Functions::
+* Group Database Functions::
+* System Information::
 * Hashing Functions::
 @end menu