Topic 3: Split othercatalognumbers for comparison between identifiers

[rukayaj]

Currently if someone has otherCatalogNumbers=a|b|c it won’t get compared with another record with catalogNumber=a.

[rukayaj]

I am not sure if it's worth doing this as it doesn't seem to be picking up any extra links (at least in our sample). Also the tests should probably go in a separate file I guess, and the code could do with being reviewed by some person who is more familiar with java.