Update Mochiweb to 2.4.2

Another one that can wait for 1.4.

Branch: 1598-update-mochiweb-2-3-2

This is a raw import of the Mochiweb repo.

I wonder if we should just commit the .git dir as well (like http://debuggable.com/posts/git-fake-submodules:4b563ee4-f3cc-4061-967e-0e48cbdd56cb)

To be done:

• integration with our Autotools, it is probably easiest (@nslater) to just usel the provided Makefile and call raw `make` instead of rewiring it all.
• we'd still need to dynamically adjust the DIST dir in src/mochiweb/Makefile
• Testing whether make / make check / make distcheck actually work, blocked by autotools integration.

Assinged to nslater for the Autotooling.