Advanced BioPAX networks merge

[IgorRodchenkov]

Implement an advanced BioPAX networks merge feature (e.g., using Paxtools Merger, the Patch tool). CyNetworks from different queries or imported from BioPAX files could be "aligned" and merged into one BioPAX CyNetwork:

this possibly can be done either before (then, everything can be coded in this app) or after a CyNetwork is created by CyPath2/BioPAX apps (then, it's probably going to be a separate app or modified core BioPAX one);
this apparently requires some form of id-mapping;
can be, in fact, a separate app...