CF support, change in FPGA-partnr & VivadoAccelerator

[vandenBergArthur]

Hi,
I have some questions:

• I noticed that the nnet files have been changed, and it no longer supports conv2d with the channels_first data format. Is this correct? Below I added a picture of the nnet file that I used before switching from pip 0.6.0 to the main branch.
  

• Could it be possible that the targeted FPGA changes if the amount of parameters in the model is too high? For example: I set the Part in the config file to xc7z020clg400-1 (pynq-z2), but after building the hls model I noticed a different target device xcku115-flvb2104-2-i from a different product family kintexu.

• From reading other issues, it is recommended to use the VivadoAccelerator backend when targeting a pynq-z2 board. Will using the Vivado backend result in errors, or will it just increase the build times?