Checked compatibility with Piwigo 2.6

Remove feature "upload picture", since it hasn't been working for months (changes on Facebook)

New languages:
* Bulgarian (Български [BG]), thanks to turnokopa
* Catalan (Català [CA]), thanks to AlbertParera, josep.torne
* Danish (Dansk [DK]), thanks to Kaare
* Portuguese Brazil (Brasil [BR]), thanks to hespanhol, flaviove
* Turkish (Türkçe [TR]), thanks to LazBoy
* Chinese (中文 (简体) [CN]), thanks to dennisyan, winson

2.5 compatibility! Thanks to the team for help.

Quick fix social plugin comment
Update pt_PT, thanks to : alahel76

- Fixed compatibility bug with Piwigo 2.4.2+
- Updated languages:
• Dutch (Nederlands NL) Thanks to Mattias
• Portuguese (Português PT) Thanks to klito

- Updated Greek (Ελληνικά GR) Thanks to bas_alba

- Compatible with Piwigo 2.4

- Updated Russian (Русский RU) translation thanks to nadusha

- Updated Hungarian (Magyar HU) thanks to asicu.com
- Updated Polish (Polski PL) thanks to voyteckst

- Added Polish (Polski PL), thanks to Greybrow

- Fixed encoding file for Spanish (Español ES)
- Updated Ukrainian (Українська UA) thanks to animan

- Added Ukrainian (Українська UA) thanks to animan

Update Hungarian (Magyar HU), thanks to : samli

New language (cs_CZ)

- Added Spanish

2.2 adaptation

Functionnalities:
-----------------
Language: update ar_SA thanks to Mohammed
Language: add sk_SK thanks to Dodo


Technical:
----------
Fix: List all Facebook locale
Fix: 2.2 adaptation by add class button

Functionnality:
---------------
Language: add ar_SA thanks to mohammed

Technical:
----------
Fix language detection
Fix picture buttons without social plugin

Functionnality:
---------------
Language: add DE thanks to sugar888
Work best with http://developers.facebook.com/tools/lint

Technical:
----------
Review meta fb:admins and fb:app_id

Tips:
-----
With LocalFiles Editor, add to local configuration this line in order identify admin of your site:

$page['fbp']['fb']['admins'] = 'nnnnnnnnnnnnnnn;

where nnnnnnnnnnnnnnn is your facebook user id
Try http://www.facebook.com/insights/

You can also add your facebook application id:
$page['fbp']['fb']['app_id'] = 'nnnnnnnnnnnnnnn';

Rollback: Reuse old method to share link

Functionnality:
---------------
Add upload button on image page
Update languages IT

Technical:
----------
New way to share link: use stream.share from the FB.ui() method of the Facebook JS SDK
Replace language by locale

Functionnality:
---------------
Add share icon on picture and album page
Add Open Graph Meta (Like Plugin Facebook Integration)
Facebook_Integration plugin is inactivated when FacebookPlug is activating
Allow Facebook to access private index page

Technical:
----------
Fix language set/detect on Facebook connect
Update language IT
Use new variables for url
Rename footer.lang.php to common.lang.php
Remove use of target attribut to open a new window

Functionnality:
---------------
Add social plugin activity feed
Update language IT
Add an option to force Facebook initialization (new way to load include file)
Add help tips on config admin page
Add promote on footer
Add promote on about page (available for Piwigo 2.2)
Add promote on admin config page
Add activity tab sheet on admin config page

Technical:
----------
Add missing index.php
Rename language files: plugin.lang.php => admin.config.lang.php
Add constants for Facebook URL
Add convert function on admin page config
Add missing options on social plugins

Next version?:
--------------
Share buttons & upload to Facebook album

Picture page:
o Fix: No like button or comments on slideshow

Language:
o Add lv_LV (Latvian) thanks to Aivars Baldone


Admin configuration page:
o Fix cancel Button
o Change layout
o Like Button and comments cannot be enabled together (php and JQuery tests)

Fix initialization of new social plugins
Use of other Facebook application ID possible

Add 2 social plugins: facepile & comments
Fix FB connexion

Add a new social plugin: Like Box
Add css
Fix translations
Disable async

Suppression des templates compilés

Version beta avec utilisation bouton "J'aime".
Les autres plugin sociaux de Facebook seront implémentés prochainement.