In extension list link to the website

[bobonov]

It would be useful to add a link to the related extension website.
Sometimes I use this list also to check what's new in php extension world, but for some of the extensions it is hard to find a reference to check what it does.
I know that when you decide to use an extension is because you already know it, but from this list you can get also "inspiration" to improve your work.

[mlocati]

Most of the packages are available either from the PECL website or from the main PHP source code.

The only exceptions are:

• composer
• blackfire
• cassandra
• geos
• ioncube_loader
• lz4
• relay
• snappy
• snuffleupagus
• sourceguardian
• spx
• zmq