Added functions for bell states and singlet/triplet states
Fixed bug in triplet_states()
Fixed bug in triplet_states()
resolved merge conflict
Removed states.py from qip module
Removed import qutip.qip.states from __init__.py
Replaced reg_str2array implementation with ket()
Removed utils module from qip
Merge pull request #157 from anubhavvardhan/add_gates

Added functions for bell states and singlet/triplet states
restructure qutip.sparse so that it is independent of Qobj. All methods should use a constistent naming sp_xxx and should only operate on sparse matrices
no global import of qutip.sparse
no global import of qutip.sparse
change qobj/entropy/metrics to use functions in qutip.sparse by passing qobj data instead of qobj
use sp_permute/sp_bandwidth instead of sparse_xxx. Only import the required functions from qutip.operator
rename test_Sparse to test_sparse
rename test_Sparse to test_sparse
fixed tests for renamed functions and isolation of qutip.sparse from qutip.qobj
more fixes in sparse unit tests for changes made in qutip.sparse
pep8 fixes in test_sparse.py
pep8 fixes in test_graph.py