solveset: dispatch to radical solving; simplify inversion code
edit public docstring
8692: watch for TypeError during checking of candidates
delay collection of dens until needed during check
real_root handles any negative arg in an odd radical
xfail same unrad test in test_solvers and test_solveset
fix RootOf._eval_Eq
minor wester mods
minor geometry test mods
minor ode mods
minor test_ode mods
minor test_solvers mods
minor test_solveset mods
unXFAIL quintics_2
quick