Makefile.end: avoid cosnet in installed Makefile
vagrant support for composite virtualbox VM

Add support for using vagrant (www.vagrantup.com) to bootstrap
a working composite development environment. Include documentation
and a line in gitignore to ignore configuration files vagrant creates
when it executes.
Vagrant.md: direct users to install virtualbox
vagrant: use explicit ssh host and port
doc: update vagrant documentation
vagrant: go back to using DHCP
Merge pull request #92 from gedare/vagrant

Vagrant
cbufp: change cbufp_collect to map and return a shared page
cbufp: use ring buffer to sync gc list

Embed a wait-free ring buffer into the shared page used to
communicate the garbage-collected cbufs from cbufp_collect.
cbufp: compile fixes
cbufp: move struct definition into interface
cbufp: change csp buffer type to intptr_t