Fix weights file 404 problem: using gdrive instead of github lfs.

[huan]

Currently, the weights files can not be downloaded in the Notebook because of the over-quota of Github LFS service.

In order to fix this, I use a script from https://www.matthuisman.nz/2019/01/download-google-drive-files-wget-curl.html to download the weight files from Google Drive.

What I had changed is the following code block:

!wget -O gdrivedl 'https://f.mjh.nz/gdrivedl'
!chmod +x gdrivedl

# !wget https://media.githubusercontent.com/media/idealo/image-super-resolution/master/weights/sample_weights/rdn-C6-D20-G64-G064-x2/ArtefactCancelling/rdn-C6-D20-G64-G064-x2_ArtefactCancelling_epoch219.hdf5
!./gdrivedl https://drive.google.com/file/d/1_1GGoHF5oq3W_iVVxx1SRDIa_mjwoe26/view?usp=sharing
# !wget https://media.githubusercontent.com/media/idealo/image-super-resolution/master/weights/sample_weights/rdn-C6-D20-G64-G064-x2/PSNR-driven/rdn-C6-D20-G64-G064-x2_PSNR_epoch086.hdf5
!./gdrivedl https://drive.google.com/file/d/1ro0Rk4xAqo-OEDGgLIYz-F0BHvmUUT2E/view?usp=sharing
# !wget https://media.githubusercontent.com/media/idealo/image-super-resolution/master/weights/sample_weights/rdn-C3-D10-G64-G064-x2/PSNR-driven/rdn-C3-D10-G64-G064-x2_PSNR_epoch134.hdf5
!./gdrivedl https://drive.google.com/file/d/1Sn9FFKXNWOPXdNzy-zmyVYB4eNRnXTKD/view?usp=sharing
# !wget https://media.githubusercontent.com/media/idealo/image-super-resolution/master/weights/sample_weights/rrdn-C4-D3-G32-G032-T10-x4/Perceptual/rrdn-C4-D3-G32-G032-T10-x4_epoch299.hdf5
!./gdrivedl https://drive.google.com/file/d/1o3l_I60xHkdiWZG7UM0nZBblEontHs2W/view?usp=sharing

!mkdir weights
!mv *.hdf5 weights

Related to #46 #59 #64