Changed QUDA_MAX_MG_LEVEL=3
Merge branch 'multigrid' of https://github.com/lattice/quda into multigrid
Added some functions to calculate the "coarse coarse" operator
Merge branch 'multigrid' of https://github.com/lattice/quda into multigrid

Conflicts:
	lib/coarse_op.cu
Merge branch 'multigrid' of https://github.com/lattice/quda into multigrid

Conflicts:
	lib/coarse_op.cu
Added functionality for more than two levels of multigrid.
Multi-level coarse operator.