Added unittest for SA host-to-device transfer
Added experimental flag to maxflow solver on device
Updated CHANGELOG and version.h to v0.4.0
fixed issue with cusparse spmm performance
Updated symmetric_rcm interface to access permutation
added OpenMP functionality in csr_to_ell and csr spmm spmv
cleaned up code
parallelized csr_to_ell host version
Fixed error in symmetric_rcm permutation
Updated gmres implementation to use abs, closes #26, closes #29
separated csr.h and csr_elementwise.h
Updated BFS implementation to remove allocations
Added more tests for views and iterator types for counting and constant arrays
Fixed error in timer destructor
Added BLAS backend and permutation matrices
Fixed bug in timer
Moved blas interface
Refined blas interface
Added missing blas_policy files
Fixed issues with BLAS backends