[ticket/11345] Change font for buttons

Change font to Open Sans

PHPBB3-11345
[ticket/11345] Add Droid Sans as fallback font

PHPBB3-11345
[ticket/11345] Move css import to template

PHPBB3-11345
[ticket/11345] Wrap remote webfonts in S_ALLOW_CDN.

PHPBB3-11345
[ticket/11345] Don't include scheme, so HTTPS is used where necessary.

PHPBB3-11345
[ticket/11895] Fix undefined $forum_id

PHPBB3-11895
Merge remote-tracking branch 'EXreaction/ticket/11895' into develop

* EXreaction/ticket/11895:
  [ticket/11895] Fix undefined $forum_id
[ticket/11890] Fix untranslated string when deleting posts through MCP.

PHPBB3-11890
[ticket/11892] Fix undefined variables: to_forum_id & to_topic_id

PHPBB3-11892
Merge remote-tracking branch 'prototech/ticket/11892' into develop

* prototech/ticket/11892:
  [ticket/11892] Fix undefined variables: to_forum_id & to_topic_id
Merge remote-tracking branch 'prototech/ticket/11890' into develop

* prototech/ticket/11890:
  [ticket/11890] Fix untranslated string when deleting posts through MCP.
[ticket/11898] Correct admin S_LOGIN_ACTION

PHPBB3-11898
[ticket/11898] Correct adm_relative_path created by installer


PHPBB3-11898
Merge remote-tracking branch 'EXreaction/ticket/11898' into develop

* EXreaction/ticket/11898:
  [ticket/11898] Correct adm_relative_path created by installer
  [ticket/11898] Correct admin S_LOGIN_ACTION
[ticket/11901] Pass empty string as relative_url for non-local magic URL.

Only the regular expression for MAGIC_URL_LOCAL has three capturing groups. As
a result $matches[3] is only set in this case. Prior to PHPBB3-11606 an empty
string was passed to make_clickable_callback() as a replacement in case of less
than three capturing groups. This patch reintroduces the empty string.

Regression from 49c12ef4be229bf2223139298766ef441b075fbc.

PHPBB3-11901
Merge pull request #1763 from bantu/ticket/11901

[ticket/11901] Pass empty string as relative_url for non-local magic URL...
[ticket/11874] Do not always prepend the web path; only replace phpbb_root_path

PHPBB3-11874
[ticket/11874] Fix tests

PHPBB3-11874
[ticket/11703] Make jQuery CDN switch more generic.

Config variable: load_jquery_cdn -> allow_cdn
Template variable: S_JQUERY_FALLBACK -> S_ALLOW_CDN

PHPBB3-11703
[ticket/11703] Add effectively_installed().

PHPBB3-11703