Minor refactor: separated parsing from loading to database.
Now storing id (such as accession id) in bio marker entry.
Adds function to add synonyms and filter duplicates.
Adds support for aliases.txt.

The entries of which are linked by the accession id to the miRNA.dat entries.
Merge pull request #2 from thehyve/issues/UAT-31_previousID_support

Issues/uat 31 previous id support