gopherjs_http: Deprecate all legacy funcs, keep only NewFS.
gopherjs_http: Deprecate all legacy funcs, keep only NewFS.

The deprecated methods were very experimental initial attempts at
serving compiled GopherJS output in a more automated way, before NewFS
was created. They're bad practices that don't scale well, and should
not be used. Mark them as deprecated.

NewFS is (overall) simpler and better, and should be used instead. Use
Package if you only need a single package.

shurcooL/go