add geometry column to sites RM-1694

- Add geometry column to sites, initialized with data (lat, lon, masl)
[masl == elevation]
- All sites are set to have srid/espg=4326 (WGS-84)
- Need to switch database.yml to use postgis instead of postgresql
improvements to spatial code

- add index to geometry
- use centroid if not a point
- remove activerecord-postgresql-adapte, is replaced by
activerecord-postgis-adapter
fixtures for testing
trait controller test
modified edit trait
show flash error
update
add comment about 4326
modified unlinking covariate
code restyle
moved citation into rescue block
update trait controller
modified rendering
fixed error on trait/new
Merge branch 'master' into RM-1694-geometry-column
modifiy @new_covariates
Removed commented-out line.
Merge branch 'phenolphtalein-edit_trait-2'

This addresses Redmine issues #2351 and #2198 and the second part of issue #2245.
Adding two images needed by the jquery-ui-1.10.4.min.css stylesheet.
(These missing images were causing rspec tests using capybara-webkit
to fail.)
Restored changes to the application layout (namely, code to display
flash errors) that were lost when the edit-trait branch was merged
into master.