define scala.home, for more robust startup of Scala tools, notably the compiler;

--- a/src/Tools/jEdit/dist-template/lib/Tools/jedit	Fri Jan 08 12:25:37 2010 +0100
+++ b/src/Tools/jEdit/dist-template/lib/Tools/jedit	Fri Jan 08 12:26:22 2010 +0100
@@ -77,6 +77,8 @@
 }
 
 declare -a JAVA_ARGS; eval "JAVA_ARGS=($JEDIT_JAVA_OPTIONS)"
+[ -n "$SCALA_HOME" ] && JAVA_ARGS["${#JAVA_ARGS[@]}"]="-Dscala.home=$SCALA_HOME"
+
 declare -a ARGS; eval "ARGS=($JEDIT_OPTIONS)"
 
 declare -a OPTIONS; eval "OPTIONS=($ISABELLE_JEDIT_OPTIONS)"