Links: should automatically add "http://" to the URI if no protocol is present

[ambrinchaudhary]

Examples:

• www.google.com --> http://www.google.com
• google.com --> http://google.com
• http://www.google.com --> no changes
• ftp://192.168..... --> no changes
• mailto://liferay@liferay.com --> no changes

If link starts with "/" we should not add any protocol.
Example:

• /blogs/test --> no changes
• //liferay.com --> no changes