[ticket/12140] Remove the diff class / MOD text build script

PHPBB3-12140
Merge remote-tracking branch 'naderman/ticket/12140' into develop-olympus

* naderman/ticket/12140:
  [ticket/12140] Remove the diff class / MOD text build script
[ticket/12147] Remove Travis CI notifications.

We don't want to get notifications for branches other people are working on.

PHPBB3-12147
Merge remote-tracking branch 'github-bantu/ticket/12147' into develop-olympus

* github-bantu/ticket/12147:
  [ticket/12147] Remove Travis CI notifications.
[ticket/12146] Added a missing # to inline css-style of <span>

PHPBB3-12146
[ticket/11509] Fail on Travis CI if commit messages are improperly formatted.

PHPBB3-11509
Merge remote-tracking branch 'Crizz0/ticket/12146' into develop-olympus

* Crizz0/ticket/12146:
  [ticket/12146] Added a missing # to inline css-style of <span>
Merge remote-tracking branch 'github-bantu/ticket/11509' into develop-olympus

* github-bantu/ticket/11509:
  [ticket/11509] Fail on Travis CI if commit messages are improperly formatted.
[ticket/11509] Contrary to docs, COMMIT_RANGE is not available in PR mode.

PHPBB3-11509
[ticket/11509] Run commit message checker only in one environment.

PHPBB3-11509
[ticket/12161] Do not use subdirectories in build/save directory.

This is pretty much pointless because a new build will wipe the save directory
and there are only a few files in there anyway.

PHPBB3-12161
[ticket/11509] Be exact when referencing the branch name.

PHPBB3-11509
Merge pull request #1999 from bantu/ticket/11509

[ticket/11509] Further improvements/fixes for the Travis CI commit message checker
Merge pull request #2001 from bantu/ticket/12161

[ticket/12161] Do not use subdirectories in build/save directory.
[ticket/12162] Set language to C before running diff to ensure its english

PHPBB3-12162
Merge remote-tracking branch 'github-nickvergessen/ticket/12162' into develop-olympus

* github-nickvergessen/ticket/12162:
  [ticket/12162] Set language to C before running diff to ensure its english