allow for uploading stl files

[jneilliii]

add the necessary bits to allow of uploading stl files

[jneilliii]

Looks like this might not be necessary as your plugin isn't registering as a slicer within OctoPrint? This came up during a discussion on Discord and this was my first thought of why you couldn't upload a stl file to OctoPrint, but even with this change, it seems the plugin isn't responding and no way to select files.

[eyal0]

Maybe the plugin is crashing when it starts? Is there anything interesting in the log files?

[jneilliii]

nothing of interest in either the developer tools of the browser or the octoprint.log. does the plugin assume a specific slicer is installed in a specific location to function? I notice the slicer pull down list is empty. I guess the larger question is how do you import an stl file into the tab?