.gitignore files, aparapi.jar removed and fixed path for MNIST datasets.

I've made few changes that enabled me to run MNIST junit tests successfully.
Not sure is the fixed RESOURCES_PATH a "best practice" (installation specific), but it makes downloading files into specific dir. easy.

Also, I've removed "aparapi.jar" from lib dir, it seems to me that it is redundant to maven version ("aparapi-2013_01_23.jar").

Please review.