Update travis docs and few other doc fixes

It's no longer needed.

Changing php version for EPV execution from 5.5 to 5.6

adding ssl-flag info for version check

EPV minim version has changed from 5.5. to 5.6:
"require": {
"php": ">=5.5.9",

Add information for CLI install and update to docu

Update Skeleton Docs

Update Skeleton extension documentation

Update the BBCodes example for forward compatibility

Merge 3.1.x into 3.2.x

Update tutorial_controllers.rst

The return value is not used in TextFormatter 1.x and tag invalidation must be explicit

Set index.htm in each folder as mandatory

Remove no longer existing language-keys from HTML-exeptions

The DBAL documentation was not included in any index and therefore didn't
show up after creating...

Fix building of documentation by switching to https docbook link

Add note about changing migrations

Add note about changing migrations

Update for 3.2.x files and links

* 3.1.x:
Add code:: to the list of files

Add code:: to the list of files

Update note about INCLUDECSS in 3.2

Merge 3.1.x into 3.2.x

[3.1.x] Fix document link

[3.2.x] Fix document link

Database Abstraction Layer documentation

Add submission guidelines to docu and updates validation.rst

Symfony changes

* 3.1.x:
[ticket/15274] Fix "custom" migration documentation

[ticket/15274] Fix "custom" migration documentation

* 3.1.x:
Install sphinxcontrib-phpdomain
Fix build with latest sphinx
[ticket/1303] CDB Li...

Fix build with latest sphinx

Remove unneeded references, remove mention to call user_func_array.

[ticket/1303] CDB Link in phpBB Development Documentation not working-1

File modified - documentation/development/language/validation.rst
WEBSITE-1303

Changes validation section to new 3.2.x guidelines

Correct 3.1 to 3.2 upgrade instructions

Add Text Formatter BBCode extension documentation

Fixes related to text formatting