Allow matplotlib plot display in pyspark context

[hafizur-rahman]

What is this PR for?

Similar to %python context, allow matplotlib plot display in %pyspark context

What type of PR is it?

Improvement

How should this be tested?

The following code should display a graph:

%pyspark
import numpy as np
import matplotlib
matplotlib.use('Agg')
import matplotlib.pyplot as plt
x = np.linspace(0, 1)
y = np.sin(4 * np.pi * x) * np.exp(-5 * x)
plt.figure()
plt.fill(x, y, 'r')
plt.grid(True)
z.show(plt, fmt="svg")
plt.close()

[Leemoonsoo]

Could you try indent code with 2 spaces like other part of codes do?

[hafizur-rahman]

Ok, giving a try...

[Leemoonsoo]

LGTM and merge if there're no more discussions.

[hafizur-rahman]

Ok, please merge

[bzz]

LGTM. BTW, this code looks very similar to the one we have in python interpreter, contributed by @bustios and @agoodm

[FRosner]

Can we have some integration test to verify this one?

[felixcheung]

where are we on this?