FIX: Inconsistent flips of ITK's displacements fields - including loading from h5#264

oesteban wants to merge 14 commits intomasternipy/nitransforms:masterfrom

codex/add-test-case-for-composite-h5-transformnipy/nitransforms:codex/add-test-case-for-composite-h5-transformCopy head branch name to clipboard