OPT: use dopy function to read bvals
OPT: use dopy function to read bvals

Former-commit-id: 89660251282d6a404d98be441d12cbf9a701379f [formerly 73723f54727bd832c9f931013221e32b81f83d0b]
Former-commit-id: 9a6b3cbc06a11dc7d253bb7408d5ed276ff33de3
Former-commit-id: e98f8ef37ac2ffe29a2c1e035e87a84ec56328d2
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox