If a filename contains dots, extension was parsed as everything after
the first dot.
File extension must be what it is after the last dot.
Also includes a rewrited workaround for mimetypes if the requested file
gzip compressed.
No need for 501 error code, as this should be returned only when needed, and will be much more efficient to not:
1.) take a table entry for the majority of cases when it isn't needed
2.) Utilize only enough memory needed to instantiate a string when it _is_ needed.
Again, nil is default for attrs not present in a table, so if you're not nil, you should just return what you know is defined. Otherwise, return the "Unknown HTTP Status" default string.
