Add event methods and tests

Depends on PRs:
- [x] #6 
- [ ]  #7  
- [x] #8 

This PR adds View Online page functionality and Links to navbars/locations functionality

Tests will fail until Prs 7 and 8 get merged
Checking a variable directly tends to be faster. Although it's an insignificant amount on a case by case basis, it's good practice for code design overall.

(!$row['page_display'] && !$this->auth->acl_get('a_')) || (!$row['page_display_to_guests'] && $this->user->data['user_id'] == ANONYMOUS)

During runtime, the entire statement may not be checked. If $row['page_display'] is true, it won't even check $this->auth->acl_get('a_'), or if (!$row['page_display'] && !$this->auth->acl_get('a_')) is true, it won't check the second half of the statement.

(don't have to change this, just something to think about in the future) :)