Revert "revert these to see if they made a difference"

This reverts commit af6e63dff10c118b42c1ed7991717c1619d5ead1.
diff --git a/build.properties b/build.properties
index 1d9647b..a698964 100644
--- a/build.properties
+++ b/build.properties
@@ -29,7 +29,7 @@
 forkValue = true
 
 # JVM options for <compc> and <mxmlc> tasks
-jvm.args = ${local.d32} -Xms64m -Xmx1024m -XX:MaxPermSize=1024m -ea -Dapple.awt.UIElement=true
+jvm.args = ${local.d32} -Xms64m -Xmx1024m -XX:MaxPermSize=1024m -XX:+CMSClassUnloadingEnabled -XX:+CMSPermGenSweepingEnabled -ea -Dapple.awt.UIElement=true
     # -d32/-d64 for 32-bit/64-bit code model (or don't specify for the default)
 	# -Xms64m: start out with a 64 MB heap
 	# -Xmx512m: allow the heap to grow to 512 MB