MIMParser: Backport further changes from ensembl-xref
MIMParser: Backport further changes from ensembl-xref

Summary:
 - new "please see the NOTICE file" copyright note
 - use confess() instead of croak()
 - add POD blocks for all functions
 - extract the part of the "extract the TI field from OMIM record"
   regular expression responsible for matching possible terminators to a
   separate regex, for better readability
 - add a beginning-of-string anchor to the regular expression used for
   the parsing of TI fields
 - a little bit of reformatting

Issue: ENSCORESW-3217

Ensembl/ensembl,Ensembl/ensembl,james-monkeyshines/ensembl,Ensembl/ensembl,james-monkeyshines/ensembl,james-monkeyshines/ensembl,Ensembl/ensembl,james-monkeyshines/ensembl