[ticket/13133] Allow @vendor_name for includecss

PHPBB3-13133
[ticket/13197] Also delete group avatar from users that have it set

PHPBB3-13197
[ticket/13204] Tell user that password was incorrect when exceeding attempts

At the end of the login method, the captcha was entered correctly and only
the password was incorrect. Therefore, just tell the user that the password
was incorrect. He will see that he still needs to enter a captcha.

PHPBB3-13204
[ticket/13284] Set message body in topic form too, so it will be sent

PHPBB3-13284
[ticket/13133] Rename $ok variable

PHPBB3-13133
[ticket/13197] Correctly format sql query

PHPBB3-13197
[ticket/13197] Fix tabbing

PHPBB3-13197
[ticket/13337] Allow empty array passed to sql_in_set()

is_array() will evaluate to true even if the array is just an empty array.
Make sure we also expect an empty array passed to sql_in_set().

PHPBB3-13337
Merge pull request #3023 from Nicofuma/ticket/13133

[ticket/13133] Allow @vendor_name for includecss
Merge pull request #3144 from marc1706/ticket/13337

[ticket/13337] Do not use SQL IN comparison with empty array
[ticket/13316] Ensure Recaptcha image uses https when necessary.

PHPBB3-13316
Merge pull request #3064 from marc1706/ticket/13197

[ticket/13197] Also delete group avatar from users that have it set
Merge pull request #3068 from marc1706/ticket/13204

[ticket/13204] Tell user that password was incorrect when exceeding attempts
Merge pull request #3108 from Elsensee/ticket/13284

[ticket/13284] Message body not included in email