Description
dualx seems to have an issue handling log scale axis.
Steps to reproduce
import numpy as np
import proplot as pplt
x = np.logspace(-1, 1, 100)
fig, ax = pplt.subplots()
ax.semilogx(x, np.sin(x))
ax.dualx(lambda x: 1/x)
The top tick labels are a mess.

Equivalent steps in matplotlib
import numpy as np
import matplotlib.pyplot as plt
x = np.linspace(0.1, 10, 1000)
fig, ax = plt.subplots()
ax.semilogx(x, np.sin(x))
ax.grid()
ax.secondary_xaxis('top', functions=(lambda x: 1/x, lambda x: 1/x))

Proplot version
3.4.3
0.9.7