refactor for OMIM cleaner code
refactor for OMIM cleaner code

* allow public methods for processing for lists of omim ids.  send in a transformation function, and iterate over the API-fetched omim records.  this makes for cleaner code, and also that external sources can call on omim methods for various functionality.
* equivalentClass -> sameAs for alleles
* add public method to create omim like 'OMIM:'+omim_num

TomConlin/dipper,TomConlin/dipper,monarch-initiative/dipper,monarch-initiative/dipper,monarch-initiative/dipper