[doc] add license information - required for NB plugin verification process
[fix] make it compatible to 7.x (could get it running for 6.9.1)
[fix] add dependency to "editor lib 2" else the buttons will not be enabled
[doc] add screenshot
[releases] add release 1.19
Merge branch 'master' of https://github.com/markiewb/nb-sort-line-tools.git