Describe the bug
When using the Bars object together with a LinearScale, the min and max attributes of the scale does affect the chart plotting areas, but the precise min and max values are not respected.

The behaviour appears to be correct for a y-axis LinearScale.

To Reproduce
import bqplot as bqp
x_sc = bqp.LinearScale(min=0)
y_sc = bqp.LinearScale()
ax_x = bqp.Axis(scale = x_sc)
ax_y = bqp.Axis(scale = y_sc, orientation='vertical')

bars = bqp.Bars(x = [10,12,14], y = [10,12,14], scales={'x': x_sc, 'y': y_sc})

fig = bqp.Figure(marks = [bars], axes = [ax_x, ax_y,])
fig

Expected behavior
The chart x axis should start from 0.

Screenshots

Environment (please complete the following information):

• macOS, Chrome, bqplot 0.11.5

Additional context
Add any other context about the problem here.