Look at relationship between Packaging System and XSLT 3.0 packages

[fgeorges]

Analyse the relationship, similarities and differences between both
"packages", how they relate to each other and how the former might
include (potentially) the latter.

Make sure to send the result back to Mike Kay, who asked for it.

For context, see the minutes of the meeting in Prague in Feb. 2015:
https://lists.w3.org/Archives/Public/public-expath/2015Feb/0005.html