[ticket/13266] Enable twig dump function

PHPBB3-13266
[ticket/13266] Enable the debug extension in the development environment

PHPBB3-13266
[ticket/13406] Add a space between the index name and columns list

Currently there's no space between the index name and columns list
when generating ADD INDEX sql query for MySQL DBMSes. This may cause errors
on earlier MySQL versions like 3.23.

PHPBB3-13406
[ticket/13098] Repair Yahoo contact field

Update the Yahoo link of the yahoo profile field.

PHPBB3-13098
Merge pull request #3099 from Senky/ticket/13266

[ticket/13266] Enabling twig dump function if DEBUG is defined
Merge pull request #3170 from Nicofuma/ticket/13266-develop

[ticket/13266-develop] Enable twig dump function
Merge pull request #3205 from rxu/ticket/13406

[ticket/13406] Add a space between the index name and columns list
Merge branch 'develop-ascraeus' into develop
Merge pull request #3229 from n-aleha/ticket/13098

[ticket/13098] Repair Yahoo contact field
Merge branch 'develop-ascraeus' into develop