Remove pylearn1 dependency throughout pylearn2

Removed pylearn1 depenceies at various spots:

dataset related:
* pylearn2/utils/utlc.py
* pylearn2/datasets/avicenna.py
* pylearn2/datasets/icml07.py
* pylearn2/tests/rbm/test_ais.py

other:
* pylearn2/pca.py
* pylearn2/packaged_dependencies/theano_linear/util.py

For the dataset related dependencies I adopted filetensor.py and utlc.py from pylearn1.

The existing datasets/avicenna.py makes use of it but it does not follow the pylearn2 dataset API.
It should probably be deprecated and removed. But for now it works as before.