Breaks When Loaded With async

[gchallen]

The way that this plugin grabs the original width and height assumes that the slides already haven't been zoomed, which seems to break when bespoke is loaded asynchronously. It seems like there should be a way to stash the original slide height somewhere so that this isn't a problem.

Anyway—it had me puzzled for a few minutes, since it still scales but leaves huge borders everywhere. Might be worth adding to the documentation somewhere, or to the main bespoke.js documentation.