emacs: Fixed performance problem when dealing with huge answers.

I have improved performance of data reception. It can handle small
signatures (eg. batteries) faster than before. Big
signatures (eg. Core) are not perfectly handled yet.
fixup perf
emacs: bound restart-process to C-c r.
emacs: correctly handles starting in non ML files.
emacs: rewind after loading a package.
emacs: fixed handling of type buffer.