Remove unimplemented user override of DefaultSummaryRows

479a311 added DefaultSummaryRows to the lsit of user-overridable
options, but failed to change any of the calls to
->Get('DefaultSummaryRows') to respect the user's setting.  Remove the
value from the list of user-configurable settings, as it would merely
serve as a default for the per-user preference already found on the
/Prefs/MyRT.html page.  Having a per-user configurable default setting
for a per-user configurable preference makes no sense.
on search by watcher load user when possible

Load user when we know that this will be one user record.
This allows us put id into SQL instead of name/email address.

EmailAddress is unique, but we don't have unique index and
can not create one until we have solution for storing NULLs
in DB.

With the change mysql can better estimate number of records
in CachedGroupMembers table and pick better plans.
clean up tmp files in REST

the reason that we unlink those files quite late is the MIME::Entity
object($ent) still makes use of them.
explicitly drop database for installer test

the db is created in installer's initialization, and RT::Test won't drop it
automatically.
Remove the "signature" paragraph from the README's explanation of RT

At one time (circa 2003) this made sense, but the explanation doesn't
need to read like a letter anymore.  There's a whole team behind RT now,
and it's one less "out of date" date to boot.
Merge branch '4.0/delete-default-summary-rows-pref' into 4.0-trunk
Merge branch '4.0/test-installer-drop-database' into 4.0-trunk
Fix version parsing in rt-setup-database

ad6a1a8 changed version parsing to use the list of possible "version
words" in RT::Handle.  Unfortunately, it made their presence mandatory,
in doing so.
RT_Config is a local link too
Merge branch '4.0/search-by-watcher-name-email' into 4.0-trunk
Merge branch '4.0/docs-rt-config-local-link' into 4.0-trunk
Merge branch '4.0/clean-rest-tmp-files' into 4.0-trunk
Merge branch '4.0/version-words-not-mandatory-in-upgrade' into 4.0-trunk
Merge branch '4.0-trunk'

Conflicts:
	lib/RT/Tickets.pm

The conflicted hunk in RT::Tickets, introduced by
4.0/search-by-watcher-name-email, has already been equivalently handled
by 4.2/search-by-watcher-name-email.