Integrate Oscar's latest optimizations, add --profile option to find-orientations, start performance analysis

[mwiebe]

These changes have been validated by comparing before/after results of the multiruby dataset. This PR includes:

• A numba-optimized version of angularPixelSize
• A vectorized simulateGVecs
• A new --profile option to the hexrd find-orientations command
• A first optimization based on the profile measurement, rewriting a special-case 2D version of np.meshgrid.
• A few more optimizations that restructure the paintGrid code to be more vectorized.