Added cache_size option to HDF5 dataset. This allows you to set the chunk cache size for the HDF5 file. This is useful when you are working with very large datasets and training performance becomes limited due to diskIO. When you store your HDF5 with large chunks (e.g. 10000 samples) and using a sequential iterator, the chunk will be loaded in memory if it fits the cache. When it is in memory, copying the batches to the GPU can happen through memory and not via disk (you only need to go back to disk for the next set of 10000 samples).
Resolve #1298

* use serial.load in CIFAR10._unpickle
* remove "scripts/tutorials/grbm_smd/make_dataset.py" from pep8 whitelist
* refine serial.load for interoparability between Python 2 and 3
* remove N and np, aliases of numpy
Fixes to load STL10 dataset

The STL10 dataset cannot be loaded because an incorrect use of parameters: y and y_labels of DenseDesignMatrix. Sanity check at _check_labels at DenseDesignMatrix was failing.
Modified error message regarding the number of channels to be more informative
Motified to comply with PR requests
merge pickle_load into serial.load
remove devtools.convert_pkl
PEP8 compliance
Merge pull request #1304 from fvisin/maxout_error_message

Improved error message
FiniteDatasetIterator gives more information when there are missing sources
Added more input validation to DataSpecsMapping
DOC filled doc string in dbm.py and sampling_procedure.py
Merge pull request #1309 from JesseLivezey/print_source

FiniteDatasetIterator gives more information when there are missing sources
Merge pull request #1310 from JesseLivezey/dataspecsmapping

Added more input validation to DataSpecsMapping
Merge pull request #1236 from GeertLitjens/master

Added cache_size option to HDF5 dataset
Merge pull request #1312 from yelite/doc-dbm

DOC filled doc string in dbm.py and sampling_procedure.py
remove the CIFAR10._unpickle method
fixed dimensions error in adult dataset
Merge pull request #1317 from tknhs/patch-1

fixed dimensions error in adult dataset
Merge pull request #1299 from euphoris/pickle

Resolve #1298