Issue #20 : (duplicate Ticket347)

[juliusHuelsmann]

Hey!

I implemented that feature (#20, #347) when I was considering to work with the labelImg tool. I did however decide against it and thus did not entirely finish a minor part of the implementation (that can be also most likely be omitted)

1. I did not finish the implementation of a rectangle angle check mechanism, that checks if the rectangle angle that is to be applied leads to a valid outcome having all edges in range of the image. That mechanism does not detect some cases where the rectangle is out of range and therefore I removed it via a boolean flag.
2. The rectangle coordinates are floating point now, I am not sure if that can be used for the rest of the pipelines / if that works in accordance with the output formats. In case it is not, simple conversion to int on export is required.

Tested only via python3.

Tracked in issue #20.