LastPostAjaxQueryPart created and getArrayParameter added in AjaxQueryPart.
Removed garbage
Updated classes list
AddPostAjaxQuery deleted and LastPostAjaxQueryPart renamed in LastPostsAjaxQueryPart
common/classes.json modified
Merge remote-tracking branch 'origin/drogue-design' into teyssier-fichiers
Documented directories structure

Moved `Post.php` to `/common/channels`.
The `local/data` shown structure is the future one, not the current.
[README] small fix
[language selector] Same appearance on both pages
[css/button] Same appearance for all buttons

We should not style them on a per-case basis.
[css/select] :hover behaviour buttons.

Factorised similar properties between inputs & selects.
An abstract class Entity for User and Channel created.
Merge remote branch 'origin/master' into teyssier-fichiers

Conflicts:
	common/channels/Channel.php
	web/php/ajax/AjaxQueryPart.php
Abstract class Entity modified and User and Channel classes extends now Entity.
AjaxQueryPart error fixed
Merge remote branch 'origin/guimier' into teyssier-fichiers

Conflicts:
	common/classes.json
	web/php/ajax/AjaxQueryPart.php
[tests] Removed empty `Channel` tests
Merge remote branch 'origin/guimier' into teyssier-fichiers
yntax error in Entity.php line 207 fixed.
ContainsIllegalCharacterException created and getActiveEntities function created.