doc tweaks
return what plot returns
fix Burkert Potential, add to top level
add burkert potential to docs
don't cover normalization setup (is tested differently)
fix pickling bugs in plotRotcurve and plotEscapecurve and test these
further tests of vcirc and vesc
better testing of nonAxi failure for plotRotcurve and plotEscapecurve
add pragmas, return plotting
add pragmas
test Rphi derivative
Test plotting of planarPotential
test RZToplanarPotential
test saving when plotting a potential
test lindbladR
test vterm
further testing of plotPotentials and plotDensities
further testing of flattening
further testing of rl
more tests of lindbladR