expand data shown on stats page

[adamrp]

Some things we might want to add:

• Number of (unique?) sequences
• Number of OTUs
• Number of biomes represented

[antgonza]

Removing easy-fix and milestone. The complexity of this issue is that currently we do not keep track of any of the sequences or OTUs statistics that were requested in the DB and to start displaying them we will need to:

• Have a patch that counts the number of seqs and otus in the hdf5 files
• Have a place to store them, perhaps the settings table?
• Display those values

Perhaps the counter can be part of #814

[antgonza]

I think this issue has been superseded by #1425. Open again if you think otherwise.