Fix some 'notice' and 'strict' issues. Add PHPDoc to headerMessagePost function in social.lib.php. Replace getSupportedImageExtensions function name with api_get_supported_image_extensions in main_api.lib.php - refs #5637
Make static getHtmlByLink function to remove a 'strict' issue. Now OpenGraph works a little better but it is still too slow so I keep it disabled (line 1515) - refs #5637
Merge pull request #412 from ilosada/5637-anibal-2

5637 anibal 2