Added optional support for JPEG-LS, JPEG and JPEG2000 transfer syntaxes

[luongthanhlam]

This PR adds logic to parse pixel data using CharLS/OpenJPEG/DCMTK if it can be imported. Tested on some compressed MR, CT and X-ray data.

[suyashkumar]

Hi @luongthanhlam thanks for the PR, I think this could be a cool way to potentially have a fallback way of reading JPEG-LS, JPEG2000 images etc, though it does come with a fair bit of toolchain overhead that I need to look into a little more and think on how/if to pull this in. Either way though, this could be a great example PR for anyone blocked on this in the short term. Some more background on the need in #85. Ideally, we would have a way to do this in Go, and I saw recently a library popped up that might help here, which might be worth a look.

[segmed-lam]

@suyashkumar Actually, anyone can write their own decoder. To register custom formats for the codec package, simply import a package which calls frame.RegisterFormat within its init() function.