Various fixes and improvements

* Improved README
* Changed config.ini to config.example.ini to indicate it's just an example
* Added exception handling to cope with a brand new address with no lessors
* Changed SCREEN sessions names to make it simpler for users to organise their sessions more easily
* Added Getting Started page with a link to a how-to video for clients
Removed the KeyError constraint on an exception block
Updated README with virtualenv instructions
Improved README readability
Merge pull request #4 from n00bsys0p/various-fixes

Various fixes