upgrade database access to be more robust

- Error messages now include a helpful list of possible
  datasets.
- modify matching of normalization type to allow unique partial submatches.
- In case this was not noted before, fixed several bugs that would associate
  the srong common name with a gene count value.
- Add option to label particular genes in addition to the most over/over expressed.
- Add option to watch more/fewer than the default 5 over/under expressed genes.
Modified comments.
Merge branch 'master' of https://github.com/cswarth/Morris-Lab