pgsql: Be less destructive, signal then clear instead.
Delay setup of backend wakeup pipe.

This delays the wakeup pipe until after the backend is actually used.

The main reason is that after fork() all copies of the process always
have the same wakeup pipe.

Waiting until the first use of the backend makes wake_up_backend()
useful again in forked processes (as long as the backend has not been
used before the fork).

Fixes a bug in turboproxy, we use a master backend system where all
modules are loaded and partially initializes in a 'master' backend,
and new backends are then forked of from the master as needed.
SSL.ServerConnection: Fixed support for resuming sessions.

It's not a good idea to send the CCS packet twice...
Image.SVG: Fixed leak on error in _decode().

The options mapping could leak in serveral error conditions.

Also adjusts some related error messages.
pgsql: Pull two Stdio.Buffers apart.
This kludges around a parser bug in Pike 8.1.

It's a bit difficult to create an isolated testcase out of this.
Somebody please look into this.

Without this patch, the following test results in the error below:

> object b=Sql.pgsql("");
/usr/local/pike/8.1.0/lib/modules/Sql.pmod/pgsql.pike:696:switch(): Conditional expression is void.