Performance regression with decoding JPEG-LS in Chrome

[chafey]

I just tested JPEG-LS lossless decoding speed in Chrome and found a major performance regression vs code 3 years ago. J2K seems unaffected and so does FireFox (did not test other codecs or browsers). The faster older code is here:

https://rawgit.com/chafey/cornerstoneWADOImageLoader/73ed7c4bbbd275bb0f7f9f363ef82575c17bb5f1/examples/dicomfile/index.html

Using CT2 image from here:

ftp://medical.nema.org/MEDICAL/Dicom/DataSets/WG04

73ed7c4bbbd275bb0f7f9f363ef82575c17bb5f1: 14 ms decode time master: 138ms decode time

[chafey]

https://github.com/team-charls/charls/issues/13