Sending large gcode files to DoodleBox

[casperlamboo]

When sending large gcode files we have to take into account a couple of things

1. Overflowing the doodle box with too many requests (see Add throttle mechanism? #10)
2. Not exceeding the 4mb size limit of the doodle box

In order to keep under the 4mb size limit there are 2 options; reject files that exceed the size limit. Send part of the file up to 4mb and wait until buffer is cleared before sending te rest. The downside of this is that the browser must stay active during the print.

[casperlamboo]

@peteruithoven do you know if it is possible to request the free disk space of the doodle box. This would help creating a very accurate system

[peteruithoven]

I'd like the api to respond with buffer is full when sending a print (part), See this issue: Doodle3D/doodle3d-client#240
I'm actually not sure what the api currently returns when it's buffer is full. I was hoping a general retry when fails (no matter the reason) would also handle this issue.
Maybe we can add more buffer size to the printer/progress api call, but I'm not sure on the implementation details.