[tdwg-tag] updated tables

[joel sachs]

I updated the "Occurrences" table by deleting the "occurrence_id" column, 
since we will be using (the hidden) "row_id" to identify occurrences. I 
created the "Identifications" table along the lines I described yesterday, 
with the addition of

a "table_id" column. So the key for the table (and guid for occurences) 
is (table_id, row_id), and we can support data from multiple 
occurrence tables.

a "taxonConceptID" column

taxonomy columns

The tables are

http://tables.googlelabs.com/DataSource?dsrcid=225363
http://tables.googlelabs.com/DataSource?dsrcid=241441

Don't be afraid to try them out -
Joel.