[ticket/11301] Explicitly cast str offset to int to prevent E_NOTICE on 5.4.

PHPBB3-11301
[ticket/11301] Guidelines: Add spaces in front and after the / operator.

PHPBB3-11301
[ticket/11313] Use correct object el instead of eel in alt_text callback

This typo was added by the PRs #860 and #1178. Only the object el exists
and is correct. Due to this the text of links using the alt_text callback
were not modified while executing the callback.

PHPBB3-11313
Merge PR #1182 branch 'bantu/ticket/11301' into develop-olympus

# By Andreas Fischer
# Via Andreas Fischer
* bantu/ticket/11301:
  [ticket/11301] Guidelines: Add spaces in front and after the / operator.
  [ticket/11301] Explicitly cast str offset to int to prevent E_NOTICE on 5.4.
Merge PR #1182 branch 'develop-olympus' into develop

# By Andreas Fischer
# Via Andreas Fischer (1) and Oleg Pudeyev (1)
* develop-olympus:
  [ticket/11301] Guidelines: Add spaces in front and after the / operator.
  [ticket/11301] Explicitly cast str offset to int to prevent E_NOTICE on 5.4.
Merge PR #1181 branch 'marc1706/ticket/11313' into develop

# By Marc Alexander
# Via Marc Alexander
* marc1706/ticket/11313:
  [ticket/11313] Use correct object el instead of eel in alt_text callback