Support for cameras that have a password set by the vendor

[markmac99]

New joiners in the UK are reporting that some camera modules are now being shipped with a different hardcoded admin password. Previously the password was blank. The DVR-IP module assumes a blank password, and doesn't allow us to easily pass any value in. However i already wanted to make changes to this lib to support Python 2.7 so at the same time i will investigate support for password protected cameras.