Bug report
Bug summary
Using bar, the first input argument is not used for the left edge of the bar, but rather the center, as if the kwarg align='center' was used. However, the desired behavior is obtained in both cases when using align = 'center' and align = 'edge'. Just when align is not specified, it should be 'edge' aligned which it is not.
Code for reproduction
import matplotlib.pyplot as plt
plt.bar([1], [1])
plt.show()
Actual outcome

Expected outcome

In matplotlib 1.5.3 I got the expected behavior.
Matplotlib version
matplotlib 2.0.0
python 3.6.0
both installed from the Arch Linux repository.