[ticket/11724] Support "ELSE IF" and "ELSEIF" in the same way

PHPBB3-11724
[ticket/11724] Replace spaces with tabs

PHPBB3-11724
[ticket/11724] Handle ELSE IF separately

PHPBB3-11724
Merge remote-tracking branch 'EXreaction/ticket/11724' into develop

* EXreaction/ticket/11724:
  [ticket/11724] Handle ELSE IF separately
  [ticket/11724] Replace spaces with tabs
  [ticket/11724] Support "ELSE IF" and "ELSEIF" in the same way