Support for FlipX, FlipY, SwapXY

[SeanLeRoy]

I came across this mention here where this package states it does not support FlipX, FlipY, & SwapXY. I've been working on improving the LIF reader for another package which uses readlif & would benefit from having the FlipX, FlipY, & SwapXY metadata to avoid having the user need to enter that information. Not entirely critical necessarily, but seemed worth mentioning that there is at least one desire out there for this feature.