Fix an oversight which disabled TTL calculation on IMS fetches.

Also make sure that objects marked uncacheable on an IMS is treated
as such.
Move doc generation into doc/sphinx and man
Don't output trailing '\0' of SLT_Debug records

SLT_Debug is special as it is both used as a binary log record and as
a text record. Add a special case for it and don't escape-output the
trailing zero.
Make the CHANGE column show negative numbers when gauges drop
Dump the objects on busyobj on panic in fetch code
Only grab the extra reference if we have a request thread that wants it.

Zeroed in on by:	scoof
Spelling
Update tutorial for 4.0
Reformat and rewrite for readability
clarity
add two params for -r consideration - and a bit for reformatting
remove cruft
Move purging into the performance section and explain its role
Add compression to performance
change commet style
Disable daemonize option for varnishtop

This option got added by misstake. Disable it as it doesn't do any
good for this application.
Remove residue of former structure
Rewrite intro
fix reference