Legacy API pull request

I've created some changes so that we can mirror the old api that the ADC uses,

http://www.camdram.net/showdata.php?type=xml&showid=2

The idea is that 
app_dev.php/legacyapi/show/slug/as-you-like-it.xml
app_dev.php/legacyapi/show/id/152.xml

will produce the same output, and we can redirect using apache. If we can get the ADC to use slugs, great - but the id one is there in case they can't because of parameter checking at their end.

Todo: create a JSON equivalent

Comments appreciated, I'm not sure if this was the best way to do it.