increase the java heap to 512M when running proguard. Otherwise the Shem build runs out of memory
building the Utopia jar file.

Change-Id: Id3491f1f8f1640aa532c5ec30353d26a8d7ff8ac
diff --git a/bin/proguard.sh b/bin/proguard.sh
index 5d441f9..b11495f 100755
--- a/bin/proguard.sh
+++ b/bin/proguard.sh
@@ -6,4 +6,4 @@
 PROGUARD_HOME=`dirname "$0"`
 PROGUARD_HOME=`dirname "$PROGUARD_HOME"`
 
-java -jar "$PROGUARD_HOME"/lib/proguard.jar "$@"
+java -Xmx512M -jar "$PROGUARD_HOME"/lib/proguard.jar "$@"