Index LibraryState usage for fast proporgation of changes

[franzlst]

• Implement and index for LibraryState usage to find very fast instances of a library without looping state machines and so on.

This index has to be build when a state machine is open or integrated into the library manager. Last option seems maybe to be the best but it is very centralized. The index should be in the library manager or at least separated from other core elements.

• Finally use the feature to implement the refresh of state machines that use changed library state machines.

Please add your opinion or come by for a discussion. The issue is related to advanced library tree features.

Finally I came to the conclusion that the cheapest implementation of the feature comes with the centralized library state generation by the library manager and library manager model and the storage of weak references of all instances in a list. Thereby the feature is also partly related to the pre-load of libraries, see issue #371, because the library manager will generate indexed elements but those are not in use.

Originally created by @Rbelder at 2017-07-12 13:19:04+00:00 (moved from RMC internal repository)