whitespace and general cleanup
converted to Java since filters are called for every request, so small performance lags add up
converted filter registration from direct wiring to using DelegatingFilterProxy. this lets you define the filter as a Spring bean and take advantage of bean builder syntax, autowiring, etc. it also makes the plugin more configurable since other plugins can change how the filters work, instead of just being able to add new processors. also converted to use OncePerRequestFilter to clean up the code