Android: Ignore the proguard folder

When exporting a signed .apk, Ecipse creates a proguard folder in the root directory. It should not be commited.

Android.gitignore

@@ -18,3 +18,6 @@ local.properties
 # Eclipse project files
 .classpath
 .project
+
+# Proguard folder generated by Eclipse
+proguard/
\ No newline at end of file