Merge pull request #44 from sdalton1/master

Added BLAS interface files
Merge pull request #45 from sdalton1/master

Fixed ambiguous namespace error
Reduced memory cost of bicgstab solver

The array 'y' is not necessary. Replacing it with 'r' can save a little
bit memory.
Merge pull request #46 from xiongzubiao/master

Reduced memory cost of bicgstab solver
Merge pull request #47 from sdalton1/master

Fixed host DIA SpMV