[optimize] Bug fix of line_search_wolfe2: Optional arguments have not been passed to myfprime if the current value of the Jacobian gfk wasn't explicitly specified by the caller. This commit is to fix this bug
[optimize] Added missing returns in docstring of line_search_wolfe2. The function returns the new function value, the old function value and the slope at the new point, in addition to the value alpha and the number of function and gradient evaluations. But this info was missing from the docstring.