workaround SBCL bug #1368764: make-condition undumpable after define-condition at non-toplevel

Use PROGN instead of PROG1 to keep toplevelness.
PPCRE system is named CL-PPCRE
connections, stuff, and stuff

Massive commit that primarily adds connections and the API to interact
with them.

Also some higher level stuff, like data structures for mailboxes and
messages.