title: Python pyqtgraph how to set x and y axis limits on graph, no autorange
body: <p>I would like to know how I can set the x and y axis limits that are displayed for a pyqtgraph.GraphicsWindow.addPlot object. I need to display a lot of data inside a loop (hence using pyqtgraph) but I would rather preallocate my axes as opposed to allowing autorange to potentially enhance speed. As an example,</p>
  
  <pre><code>from pyqtgraph.Qt import QtGui, QtCore
  import numpy as np
  import pyqtgraph as pg
  app = QtGui.QApplication([])
  win = pg.GraphicsWindow(title="My plotting examples")
  win.resize(1000,600)
  win.setWindowTitle('pyqtgraph example: Plotting')
  p1 = win.addPlot(title="plot1")
  p2 = win.addPlot(title="plot2")
  curve1 = p1.plot(pen='y')
  curve2 = p1.plot(pen='r')
  curve3 = p2.plot(pen='b')
  x = np.linspace(0,10,1000)
  x_current = x[0]
  p1.setXRange((5,20), padding=0)
  for i in range(1,len(x)):
      x_current = np.append(x_current,x[i])
      curve1.setData(x_current,np.sin(x_current))
      curve2.setData(x_current,np.cos(x_current))
      curve3.setData(x_current,np.tan(x_current))
      app.processEvents()
  
  if __name__ == '__main__':
      import sys
      if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
          QtGui.QApplication.instance().exec_()
  </code></pre>
  
  <p>The problem lies in the line <code>p1.setXRange((5,20),padding=0)</code>. This results in the error: TypeError: setXRange() takes at least 3 arguments (3 given)</p>
  
  <p>I think this should be a very simple question, just setting the axis ranges before plotting. </p>