Build #1294, Build #1297, #1301, #1303, #1305, #1306, #1308

PHPBB3-12251
Clean up and Enhancement of Custom Profile Fields
PHPBB3-12106
Document exceptions to "Disable Board" in ACP
PHPBB3-10549
Languages variables should be used, not hardcoded
PHPBB3-12244
Remove ambiguity between Extension Tab and Extensions Management links
PHPBB3-12176
No error shown when attempting to delete a founder
PHPBB3-8785
PM to list looks bad
PHPBB3-8041
Some cosmetic things for translation(s)
PHPBB3-11787
Permission language strings use samp for highlight instead of strong