Pin to currently-published version, although there is a known (minor)
floating-point precision bug with multipleOf, fixed upstream but not
released yet.

SlapOS already relies on system binutils and
version 2.21.1 does not compile with recent GCC.

Conflicts:
	stack/erp5/buildout.cfg

All parameters about SLA, i.e. computer-guid & instance-guid, are removed in
favor of a new "sla-dict" parameter, which is easier to implement and much more
versatile.

All changes in the request parameters are incompatible. The old ones are
ignored without warning/error.

For compatibility, the reference of ZEO partition is still "zodb".

Default settings were also fine. Default name of mount-point and FileStorage
file is reverted to 'root' instead of 'main'.

also fix a few typos and reference to slapgrid

TIDStorage is used to manage backups but most of time the DB is not splitted
and there's no need to run a TIDStorage daemon.

We now use a version of ZEO that support ipv6 natively so this is useless.

Although TIDStorage only supports ipv4, it's easier and better to fix TIDStorage
rather than maintaining such hack in SlapOS.

Most of the time, the logging process keeps the log open, accesses it via
a file descriptor and gets notified of log rotation via a signal. Because
logrotate does not wait that the log is close (could it do it with inotify ?),
there can be race conditions between the compression and events that are logged
at the same time.

In the case of NEO, logs are SQLite DB. Rotation is also notified via a signal
and VACUUM is sometimes called to reduce its size.