Asset support

[ipjohnson]

I'd like to be able to serve static assets for an SPA using EasyRpc. I'm not happy with the middleware for static files work as it lacks a lot features needed for SPA. Here are the requirements

• support in memory cache
• support on the fly compression (when cached)
• support compile time compression without having to request a file with the extension .gz or .br
• support authorization
• support filters
• support fallback (return specific file even if it doesn't match)
• support cache control header out of the box (it will set it by default)