Short description

When I try to plot with error bars having values smaller than 1e-12, they do not show up. No error or warning.

Code to reproduce

import pyqtgraph, numpy

ey = numpy.array([2e-12, 1.1e-12, 1e-12, 0.9e-12])
p = pyqtgraph.plot()
p.addItem(pyqtgraph.ErrorBarItem(x=[0,1,2,3], y=[0,0,0,0], top=ey))

Expected behavior

We should see 4 bars of diminishing height.

Real behavior

We see only the first two.

Tested environment(s)

• PyQtGraph version: 0.10.0
• Qt Python binding: PyQt5 5.9.2 Qt 5.9.6
• Python version: 3.7
• NumPy version: 1.15.4
• Operating system: Linux Mint 19
• Installation method: conda

Additional note

PlotCurveItems appear with crazy small values, well below 1e-12, but their error bars don't. This confused me for a long time!

Thanks in advance, and sorry if this issue is fixed in 0.11 already.