Node API - Cannot add/push package changes multiple times

[Blasz]

We're using yalc via node instead of running it via the commandline and have noticed that changes made after an initial push never make it to the installation dirs.

After debugging the code, I've found that the cause is the implementation of copyDirSafe which caches the contents of the package in memory which ignores any subsequent published changes to the package in the yalc store.

This works fine when run via the commandline since a package will only be added/pushed to a repo once in yalc's lifetime, however, this is not the case when running in node.