Major JPM update jpm:1.2.0

[jpm-hub]

In this new jpm update, we've addressed a drawback that many complained about on the npm side.
The thing is, jpm_dependencies behaved like node_modules for a while, until now, every download is now in a single position :

./jpm/libs

and all jars are now hardlinked to jpm_dependencies which makes it use considerably less space on the disk for multiple projects and brings the tool closer to the big players such as maven and gradle.