Issue/21 language system changes in 3.2

[nickvergessen]

• Depends on Add a sample how to load an extension language file #36

@MateBartus please review 6bf972a

[CHItA]

phpbb\language\language::add_lang() first argument array of the language files, second argument is the name of the extension

[nickvergessen]

@CHItA updated

[CHItA]

add_lang() as well for exts, as in the examples below

[nickvergessen]

hmpf must have slipped through

[nickvergessen]

Updated

[iMattPro]

Add a bit about the new lang system replacement for LA_KEY by doing {{ lang('KEY')|e('js') }}
Other possible options:
{{ lang('KEY')|escape('js') }}
{{ lang('KEY')|e('addslashes') }}
{{ lang('KEY')|escape('addslashes') }}

addslashes is our own custom func that simply addslashes the string.
js is a native twig function that escapes a string for the JavaScript context.

[nickvergessen]

@VSEphpbb since those comments need to go into 3.1 aswell, please create a new issue (and feel free to prepare a patch ;) )