[task/github-readme/travis] Fix Travis-Badge and link

PHPBB3-11968
Merge branch 'task/github-readme/travis' into develop-olympus

* task/github-readme/travis:
  [task/github-readme/travis] Fix Travis-Badge and link
Merge branch 'develop-olympus' into develop

* develop-olympus:
  [task/github-readme/travis] Fix Travis-Badge and link
[ticket/11920] Pin MariaDB repository to avoid conflicts with Ubuntu MySQL.

PHPBB3-11920
Merge remote-tracking branch 'bantu/ticket/11920' into develop-olympus

* bantu/ticket/11920:
  [ticket/11920] Pin MariaDB repository to avoid conflicts with Ubuntu MySQL.
Merge branch 'develop-olympus' into develop

* develop-olympus:
  [ticket/11920] Pin MariaDB repository to avoid conflicts with Ubuntu MySQL.
[ticket/11970] Add set -x to Travis setup scripts.

Output is hidden by Travis by default and this will allow easier debugging.

PHPBB3-11970
[ticket/11970] Make apt-get less quiet.

PHPBB3-11970
Merge remote-tracking branch 'github-bantu/ticket/11970' into develop-olympus

* github-bantu/ticket/11970:
  [ticket/11970] Make apt-get less quiet.
  [ticket/11970] Add set -x to Travis setup scripts.
Merge branch 'develop-olympus' into develop

* develop-olympus:
  [ticket/11970] Make apt-get less quiet.
  [ticket/11970] Add set -x to Travis setup scripts.
Merge pull request #1817 from cyberalien/ticket/11956

More responsive design adjustments
[ticket/11957] Viewport meta

PHPBB3-11957
[ticket/11957] Viewport meta for install_update_diff

PHPBB3-11957
[ticket/11957] Replace corner images with CSS3 corners

PHPBB3-11957
[ticket/11957] Remove menu toggle

PHPBB3-11957
[ticket/11957] Responsive layout and menu

PHPBB3-11957
[ticket/11957] Include admin.js in footer

Include admin.js in footer, swap .hasjs and .nojs

PHPBB3-11957
[ticket/11957] Enhance responsive nav with JS

PHPBB3-11957
[ticket/11957] Adjustments to ACP layout, menu and some elements

PHPBB3-11957
[ticket/11957] Use fixed width for sidebar

Use fixed width for sidebar and few minor fixes for other items

PHPBB3-11957