Canceling a bulb exposure early with the shutter button, automatically stops the intervalometer if it’s running

Created originally on Bitbucket by dmilligan (David Milligan)

Was already merged in Bitbucket before import, marked as merged by the import user

I use "like crazy" mode and long bulb timer exposures (2+ mins) a lot for astro, problem is that it's hard to stop the intervalometer. If you do this, basically the only way is to turn the camera off. This change allows you to stop the intervalometer by canceling a bulb exposure.

Still need to find a way to do something like this when in regular exposure mode (not bulb). Perhaps it's possible to detect a half or full shutter press even during an exposure?