[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
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.