Confirmed via
http://dan.munckton.co.uk/blog/2013/06/21/go-lang-packaging-creating-a-library-that-bundles-an-executable/
that server src dir is ok within main package dir, and declares itself
as package main.  Started server by generating random id of sufficient
length to make practically unique.  This will be used by a lock file
residing in a logbase dir to indicate that this server instance is
managing this logbase.
Generally moving server forward and tidying a bit.

- Moving as much of server code into logbase/server.go as possible, away
from executable.  Means tests for server can also be brief.
- Reduced lines in errors.go and starting to introduce fluent interface
(so actions can be chained together). Did this in a few places in debug.go
too, more to go.
- A server will generate its own debug log and in practice this will
usually be used by all its managed logbases.