Docblock fixes

- Removed unwanted @return void from __construct DocBlock
- Improved DocBlocks for @return, @throws and Namespace casting

Note: __construct always return void and no need to add doc statement for same. IDEs like PHPStorm give error on return statement on __construct and fails on code inspection.

![screenshot 2014-04-30 09 11 44](https://cloud.githubusercontent.com/assets/371606/2837469/52c074e0-d019-11e3-97d6-8177ae43e6e0.png)