Input matricies need to be int32

[jattenberg]

Often arrays are created into different types than what is required by the lightfm c code. this can result in errors like:

File "/home/jattenberg/anaconda/lib/python2.7/site-packages/lightfm/lightfm.py", line 194, in fit verbose=verbose) File "/home/jattenberg/anaconda/lib/python2.7/site-packages/lightfm/lightfm.py", line 254, in fit_partial self.loss) File "/home/jattenberg/anaconda/lib/python2.7/site-packages/lightfm/lightfm.py", line 289, in _run_epoch CSRMatrix(self._get_positives_lookup_matrix(interactions)), File "lightfm/lightfm_fast.pyx", line 91, in lightfm.lightfm_fast.CSRMatrix.__init__ (lightfm/lightfm_fast.c:1966) ValueError: Buffer dtype mismatch, expected 'int' but got 'long long'

input matricies can automatically be converted to int32

[maciejkula]

Solved in #22 and deployed to pypi as 1.4. pip install lightfm==1.4 should get the new version.