Declare scipy optional (#1067)

* Replace use of scipy.random with numpy.random

* Update README to reflect scipy being an optional depenency

README.md

@@ -22,8 +22,9 @@ Requirements
 * PyQt 4.8+, PySide, PyQt5, or PySide2
 * python 2.7, or 3.x
 * Required
-  * `numpy`, `scipy`
+  * `numpy`
 * Optional
+  * `scipy` for image processing
   * `pyopengl` for 3D graphics
     * macOS with Python2 and Qt4 bindings (PyQt4 or PySide) do not work with 3D OpenGL graphics
     * `pyqtgraph.opengl` will be depreciated in a future version and replaced with `VisPy`

examples/MultiPlotWidget.py

@@ -3,8 +3,7 @@
 ## Add path to library (just for examples; you do not need this)
 import initExample
 
-
-from scipy import random
+import numpy as np
 from numpy import linspace
 from pyqtgraph.Qt import QtGui, QtCore
 import pyqtgraph as pg
@@ -22,7 +21,7 @@ pw = MultiPlotWidget()
 mw.setCentralWidget(pw)
 mw.show()
 
-data = random.normal(size=(3, 1000)) * np.array([[0.1], [1e-5], [1]])
+data = np.random.normal(size=(3, 1000)) * np.array([[0.1], [1e-5], [1]])
 ma = MetaArray(data, info=[
     {'name': 'Signal', 'cols': [
         {'name': 'Col1', 'units': 'V'},