linuxparty.sh: disable math section

The only math package we have is singular - which is broken on
ubuntu 15.10 (up to now). Disable the whole section.

scripts/linuxparty.sh

@@ -499,12 +499,13 @@ then
   install_if
 fi
 
-if askyesno "Software für Mathematik installieren ?"
-then
+#FIXME: currently singular cannot be installed on ubuntu 15.10 (this is the only package in the math section)
+#if askyesno "Software für Mathematik installieren ?"
+#then
   #apt-install haskell-platform java7-jdk swi-prolog
   #ok "Haskell, Java, Prolog und Eclipse wurden installiert"
-  install_m
-fi
+ # install_m
+#fi
 
 if askyesno "Software für Physiker (Python-SciPy,-NumPy,diverse Plot-Programme) installieren ?"
 then