Get a list of all build mails. (Open mails are not being showed).
The following errors can occur:
- Token not present in request.
- Token not in the required format.
- Session does not exist.
- Session has expired.
- The user does not exist.
- No database specified.
- Database parameter not in correct format.
- You are not allowed to access this database.
You should call this function as followed:
- rest/v2/link/getCount?token=TOKEN&database=DATABASE_ID&usable=true&since=2015-01-31%2010:15&offset=0&records=25
            
                require_once 'Rest.php';
                $username = 'my_username';
                $password = 'my_password';
                $database = '999';
                $rest = new Rest($username, $password, $database);
                $result = $rest->call('mail/all', [
                	'usable' => 'true',
			'since' => '2015-01-31 10:15',
			'offset' => '0',
			'records' => '25'
                ], 'POST');
                var_dump($result);
            
        
    
                                                            The following parameters this method can/should be called with:
key:    usable
values: 1, true, yes
what:   Shows you only the mails you can use for mailing (sendContinuesMail, etc.)
key:    since
values: string, String, any value that can be converted by php/strtotime, required
what:   date from which the records must be retrieved
key:    offset
values: integer, >= 0 & <= count, defaults to 0
what:   The offset the result-list should start at.
key:    records
values: integer, >= 5 & <= 50, defaults to 25
what:   How much records you want to retrieve
The following items:
- user/login         For the TOKEN
- user/database      For the DATABASE_ID