forum MDL-22477 Fixed single discussion forum so it works, and also fixed a bunch of other little regressions and bad formatting while there.  Blog forum now 100% wide too.

Strings related to users uploading moved into admin.php component. Fixed
calling of new help strings. Fixed incorrect strings call.
The script also copies instructions from two previous commits as I
forgot that the commit must touch some string file to being parsed by
amos.

AMOS BEGIN
 HLP uploadusers3.html,[uploadusers_help,core_admin]
 HLP uploadusers2.html,[uploadusers_help,core_admin]
 HLP uploadusers.html,[uploadusers_help,core_admin]
 HLP uploadpictures.html,[uploadpictures_help,core_admin]
 MOV [uploadusers,core],[uploadusers,core_admin]
 MOV [uploadusers_help,core],[uploadusers_help,core_admin]
 HLP cookies.html,[cookiesenabled_help,core]
 HLP overrides.html,[overridepermissions_help,core_role]
 HLP permissions.html,[permission_help,core_role]
AMOS END

AMOS BEGIN
 HLP cookies.html,[cookiesenabled_help,core]
AMOS END

AMOS BEGIN
 HLP overrides.html,[overridepermissions_help,core_role]
 HLP permissions.html,[permission_help,core_role]
AMOS END

MDL-22015 Added a new setting langstringcache to enable/disable the string caching. Developers will want to switch this off. :)

portfolio & online assignment    MDL-22485 require portfoliolib & check portfolios enabled before trying to add buttons

MDL-22479 Added a check for $CFG->siteadmins being empty, then try to recover.  Avoids upgrade issues.

course publish MDL-19315 fix improper use of moodle form (=> require values go now through validation)

old admin blocks MDL-22475 Goodbye admin and admin_tree.  You were good to us.  But now we have Settings.

thanks to Jay Knight for the patch

The results of merged en + en_local + parentlang + parentlang_local +
lang + lang_local are now saved into disk cache in dataroot/cache/lang/.
The number of get_string() calls, and number of mem cache and disk cache
hits are part of performance logging.
Disk cache must be removed whenever the language packs or their local
customizations are deleted. Disk cache is rebuilt automatically.