Demo optimise - unpaired ct lung

[s-sd]

Subject of the issue

improve results from the unpaired_ct_lung demo

[YipengHu]

@s-sd how far are you into this? since I am at it, i can take this over if you want?

[s-sd]

@YipengHu, I am working on this now (the model is currently training). Will hopefully submit a PR for it tomorrow or later today