Made the Ensemble#to_s method handle the case where the notes
attribute is nil: It now returns the empty string in this case.  This
allows the Run editing page to be accessible in the case where the
ensemble associated with the run being edited has a NULL notes column.
Update production_structure.sql after running these migrations:

	add_model_type_to_pfts
	add_posteriors_ensembles
	fix_posteriors_ensembles
Changes to sites listing and to species show page in connection with Redmine issue #1752.
Merge branch 'MarvinJ-master'
Changes to the species show page in connection with redmine issue #2211 and changes to the user controller and display of user link in menu in connection with redmine issue #2186.
Merge branch 'MarvinJ-working'
Added citation author and citation year to the list of columns that
the advanced search will attempt to match on.  Modified the
AdvancedSearch module to treat textual and non-textual columns
differently.  This addresses most of the feature request in Redmine
issue #2333.
Fixed site integration test (resolves Redmine issue #1752).

Author:    MarvinJ <hjiang13@illinois.edu>
Merge branch 'MarvinJ-change_test'
Merge branch 'master' of https://github.com/PecanProject/bety into feedback
updates