Seaborn Restore marker edges
A solution to this is after importing seaborn do the following:
matplotlib.rcParams['lines.markeredgewidth'] = 1
Apparently, importing seaborn sets the marker edges in a matplotlib.pyplot.plot to zero or deletes them. 
e.g. plt.plot(x,y,maker='s',markerfacecolor='none')
results in a plot without markers. 
Is there a way to get the edges back?
markeredgecolor='k' has no effect.