<base/pump>, for non-blocking writes for on-box pipes.
<base/subprocess>, for non-blocking writes between parent and child processes.
<base/rigid_subprocess>, for blocking writes between parent and child proceses.

Note that the two subprocess classes don't have unit tests. Still working out
how to do that with our current testing framework.
Started <stig/mynde/binary_protocol.test.cc> but have found that the
server (1) requires an instance name to avoid throwing during start
(don't know why that should be in mem-test mode) and (2) is seg-faulting
during shutdown.  This push is to help Joris diagnose.
Trivial binary protocol test (Send a binary request), currently hanging.
Make writing request and response headers not magically become varint writing which messes up our byte counts
Merge pull request #179 from cmaloney/mynde_unit_test

Mynde unit test