Type hinting with "self" keyword in interfaces causes fatal error.

When I mock an interface with a method containing "self" keyword I get a fatal error.

``` php
use \Mockery as m;

interface MockeryTest_InterfaceWithMethodParamSelf {
    public function foo(self $bar);
}

m::mock('MockeryTest_InterfaceWithMethodParamSelf');
//Fatal error: Declaration of Mockery_518f8926abab9::foo() must be compatible with that of MockeryTest_InterfaceWithMethodParamSelf::foo() in mockery\library\Mockery\Generator.php(129) : eval()'d code on line 1
```

I've made a correction and a test to reproduce it.