[2.0.7] Inserting tracker/counter code (SEO module)

[phuoc69]

TomatoCMS already supports inserting Google Analytic tracker code to your website via gatracker hook.
We want to improve the TomatoCMS hook system and using the hook in this case is not really nice. It is more beautiful if we create a plugin for this purpose (with this approach, not only TomatoCMS but also other Zend Framework based applications can use the idea how to implement this)

Also, this plugin allows user to insert tracker code of most popular analytic systems, such as:
- Google Analytic
- Hitstats