plotting API should support custom tick labels

[Thomas Gilgenast]

currently @plotter and therefore adjust_plot() both support xticks and yticks kwargs, but there is no way to pass a (positions, labels) tuple here that would end up getting passed as plt.xticks(positions, labels)

the current workaround is to not use the adjust_plot() API and just manually call plt.xticks() but this is not ideal

[Thomas Gilgenast]

a minimal test case for this is

import matplotlib.pyplot as plt

from lib5c.util.plotting import plotter

@plotter
def plot_fn(x, y, **kwargs):
    plt.scatter(x, y)

plot_fn([2, 3], [3, 4], xticks=([2, 3], ['cow', 'say']), outfile='test.png')

‌

[Thomas Gilgenast]

fixes #25

→ <<cset 0ca19a64f169>>