Add autoclean for scripted use

  ./runprebuild.sh autoclean - cleans projects w/o prompting

runprebuild.sh

@@ -9,21 +9,34 @@ case "$1" in
   ;;
 
 
+  'autoclean')
+
+    echo y|mono bin/Prebuild.exe /clean
+
+  ;;
+
+
   'vs2010')
   
     mono bin/Prebuild.exe /target vs2010
   
   ;;
 
+
   'vs2008')
+
     mono bin/Prebuild.exe /target vs2008
+
   ;;
 
+
   *)
 
     mono bin/Prebuild.exe /target nant
     mono bin/Prebuild.exe /target vs2008
+
   ;;
 
+
 esac