WS280 Species model additions

[Paul-Davis]

Kimberly and I would like to add a few tags to the ?Species model.

• Top level Evidence tag to store provenance, Who, Why, and a remark

• A dedicated "References" tag specifically in the main object model which would also allow the option of an XREF.

• Remark to allow for text comments when Species names change or other meta data is modified so that evolution of the object can be tracked when curators are looking at the object in the future.

  > ?Species Evidence #Evidence                // Meta data for why the object was created
        Short_name UNIQUE Text             // e.g. 'C. elegans'
        Other_name Text                    // sp. 7 etc.
        G_species UNIQUE Text              // e.g. 'c_elegans' - used internally for file generation
  >         References ?Paper     (optional XREF Species_in_paper)
  >         Remark ?Text #Evidence
        NCBITaxonomyID UNIQUE Int
        In_analysis ?Analysis XREF Species_in_analysis
        Assembly ?Sequence_collection      //used for linking to the species assemblies

[Paul-Davis]

Paper class already had a Refers_to Species ?Species tag so just converted this to an XREF

Species ?Species XREF Reference #Evidence