Month names overlapping in graphs/master

Summary

Month names are overlapping in a graph view for some busy repositories.

Steps to reproduce

Open a graphs view of a busy repository. (NOTE: I wasn't able to reproduce this myself, but I think it's reproducible, plus it was reported by an user.)

Expected behavior

Month names should have some spacing in between.

Actual behavior

Month names do not have sufficient spacing and some overlap.

Relevant logs and/or screenshots

Reported by user:
https://twitter.com/tuxt3r/status/811948421972160513