MDL-18797 string_manager::instance()->get_registered_plugin_types() does not return "__exceptions" as places_to_search_for_lang_strings() used to do.

MDL-16002 rewritten upgrade locking and better upgrade progress tracking; MDL-16070 Do not use $a[0] syntax in lang packs + various other upgrade improvements and fixes

MDL-15738 Always use <textarea> in language translation form, even for short strings. Merged from MOODLE_19_STABLE

The very last save button is tabindexed, too. Forgot to include it in the last commit. Merged from 19_STABLE

Save buttons are tabindexed as well. You don't need to touch the mouse at all ;-) Merged from MOODLE_19_STABLE

Merged from MOODLE_19_STABLE. Do not produce PHP warnings in case string file does not define array $string[]

Fixes notices produced by PHP when saving new strings into _local without corresponding master translation.

Merged from MOODLE_18_STABLE

Introducing two new functions lang_standard_locations() and lang_extra_locations() as a part of solving MDL-9361.

TODO rewrite the code to work with array returned by these functions.

* MAJOR CHANGE: lang.php now uses two new core capabilities. With them, site admin may control who is able to edit master language packages (nobody by default) and who is able to customize local translation (legacy:admin by default). See MDL-10576 for details.
* More GUI improvements and code cleaning

Repeating the skodak's commit 1.95 (MDL-9647 simplify dealing with headers/footers in admin sections) - evidently too late for me tonight... doing more CVS mistakes :-(

* Started to work on GUI improvements. Menu tabs introduced. Heading to fix MDL-8012
* "Number of missing strings" or "No missing strings" displayed in the missing mode. Fixes MDL-7029

This commit covers changes from 1.88.2.5 to 1.88.2.8 which were accidentally done on MOODLE_18_STABLE instead of HEAD.

MDL-9563 Improve refreshing of langcache, detect permission problems

merged from MOODLE_18_STABLE

Now we can go to a missing docs/help files directly via a link. Thanks to Mitsuhiro Yoshida for the patch.

Merged an fix from MOODLE_18_STABLE: Fixed and error in rendering different background color of the row in non-editable environment.