suzerain: #2164 add plot_tke

# Use as follows assuming Matplotlib text.usetex = True
import perfect
A = perfect.Data('/h2/rhys/Desktop/coleman3k15.h5')
ax = perfect.plot_tke(A)
ax.set_title('Coleman3k15 TKE Budget')
ax.set_xlabel(r"$y/\delta$")
ax.set_xlim([0,1])
ax.legend(loc='best')
plt.show()

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@45404 0bd85f0b-c151-43b9-a1e9-27231104551f