Auto generated ref code numbers would be a useful option when adding new references

[GoogleCodeExporter]

Enhancement request from Dieter Slos.

The enhancement calls for a facility that accepts a ref code prefix (based on 
author name, for example), and the searches the database for existing ref codes 
with that prefix, finds the largest existing number suffix, and increments that 
number yielding a new unique refcode with that prefix.

Original issue reported on code.google.com by david.ba...@gmail.com on 16 Jul 2013 at 10:57