Added convenience loggers and centralized the cache directory finding

I ripped out the FROYO and GINGERBREAD compatibility code since you are already targeting API level 16.  I also made some helper loggers so you don't have tags running around everywhere.  

I did try and test it out, but I don't really see any unit tests to run so I am not certain everything is hunky dory.  If you plan on maintaining this over the next year(s), it would be worthwhile to add unit tests because they really help with refactoring. (the also serve to make you make your code more modular and double as documentation).