Xdeps version 0.8.0

Changes:

• Introduce MeritFunctionView(..., rescale_x=...), MeritFunctionView.get_jacobian()
• Introduce Optimize.from_callable()
• Introduce Optimize.run_ls_trf(...), Optimize.run_ls_dogbox(...), Optimize.run_l_bfgs_b(...), Optimize.run_bfgs(...), Optimize.run_simplex(...)
• Introduce Optimize.step(..., take_best=True)
• Optimize.targets and Optimize.vary can be accessed with tags

Full Changelog: v0.7.4...v0.8.0