Fix packing +UPGRADE scripts

Fixes: #518
Merge branch 'master' of github.com:freebsd/pkg
Bring pkg-search into the new repository world order:

   - PKG_MULTIREPOS is gone
   - There's no special "multirepo" mode any more
   - Use of ${LOCALBASE}/etc/pkg/repos
Bring pkg-update into line with current practice

   - No more PKG_MULTIREPOS
   - Repo catalogue updates are normally automatic
   - Unless disabled by REPO_AUTOUPDATE being false
Update to describe the new repository world order:

   - No more PKG_MULTIREPOS
   - No more multirepo mode
   - Refer to new pkg-repository.5 man page describing how
     packages are selected from the available repositories.
Substantial rewrite of pkg-upgrade to describe the program's mode of
operation, in line with pkg-install.8.  Copy some of the new material
back to pkg-install.8.

   - No more PKG_MULTIREPOS
   - Refer to new pkg-repository(5) man page describing how packages
     are selected from the available repositories.
Repo config files have to match *.conf
Fix grammar.
Add forgotten Makefile

Reported by:	matthew@
Merge branch 'master' of github.com:freebsd/pkg
Translate from the Franglais.
Ignore the various generated scripts
New pkg-repository(5) man page
Add a reference to the optional filesite.tgz

Make it clearer there's only one URL per-line in the HTTP
mirroring scheme