…up calculations

…ch the convention in obspy.

"from obspy.taup import traveltime_plot"

added add a short paragraph with timeplot method and traveltime_plot() function
to the docstring.

- removed redundant "optional" to kwargs with default values
- fixed the default mention on the model parameter (not on type)
- fixed typo in call to example plot

…rapper function.

…ot() method for ray paths. Added convenience wrapper functions for both.

In the test_plotting and tutorial, I added these new features and streamlined some naming conventions, so that the file names of these plots
more accurately represent what is in them.

+ax = plt.subplot(111, polar=True)
+fig = ax.figure

to

fig, ax = plt.subplots(polar=True)

in docs of tau.py and in the code snippet ray_path_plot.py

…d to plot_rays(). New convenience functions travel_time_plot() and ray_path_plot() wrap around the respective methods. The Gallery and testing environments contain new examples to illustrate these.

…path plot.

…le for mpl <2.0.2.

…name of the method (and to be consistent with the method and snippet plot_travel_times.py.

…pet plot_ray_paths.py

…ly fixed now!

…negative epicentral distances.

… by default. Also increased the distance between symbol phase name label slightly, so it holds up on a smaller figure.

default internally is nicer

traveltimes for both directions at individual epidistance, i.e. the
normal Jeffreys/Bullen plot style)

testing

indentation

plot type (Spherical/cartesian)

this can be used in tests that should fail and then might attempt to
upload images which takes several seconds and is totally unwanted in
this case

…mits

also sanitize ax/fig kwarg handling in one routine