Lang spanish

Hi!

First, sorry for my english... I'm spanish, and I speak english not very well...
I'm very happy with SquidAnalyzer, its a very good product... so I decided to add the spanish lang support, so if you consider that these changes are a good idea, feel free to add the commits to your code. 

The changes are very simple, just a new file with the lang and a pair of modifications to add the new language.

Thanks,

Regards from Spain,