Preference to toggle auto-rendering. Could save processing power on large documents.
Change auto render flag to "manual"

This is better for backward compatibility since non-existent flags
would be NO by default, and we want to keep the original behaviour
which enabled auto rendering.
Add menu seperator
Add Jonathan Como (@jcomo) as contributor

Fix #11
Use CFBundleVersion in preferences

This is better because CFBundleVersion is strictly incremental,
and can provide finer control to key changes.