Base URLs Don't Encode Properly Without Terminating Slash

[tmountain]

DEFAULT_SETTINGS = {
    "base_open_tracking_url": "http://pixels.example.com/track/",
    "base_click_tracking_url": "http://clicks.example.com/track?"
}

Given the example above, the base_open_tracking_url looks like this (correct):

http://pixels.example.com/track/

The base_click_tracking_url excludes the track? portion.

http://clicks.example.com/eyJ1cmwiOiAia...

The base URL should accommodate both scenarios.