* validate web-asset-base-dir
* move default icons into converter
* always ensure avatar + header on api accounts
* update tests
* add default header
* don't return error from web module creation anymore
* tidy a bit
* use pngs for default avatars rather than svgs
* start working on etag stuff
* add + use cache middleware
* generate etags on the fly
* remove unused field
* clean up filepath
* add license headers to cache files
* add attachgroup function to router interface
* move cache into web module
* rename a couple things
* remove attachStaticFS function from router
* rename + tidy up a few things
* mount assets filesystem
* create assetsFileInfoCache
* update comment
* simplify hash
* fix string fmt
* skip last mod chk, prefer strong etags w/long cache
* move base handler to its own file
this matches the modules in the api folder
* generate new etag if file was modified
* wrap strong etag in quotation marks as per spec
* clarify logic in avatar search
* make hashing a little niftier
tobi