Add a migration to load all iTree regions

Deb gave the ok to include these in repository. The data in this
migration was generated from an updated region shape file from which the
lakes have been removed.
Merge branch 'master' of github.com:azavea/OTM2 into topic/add-all-itree-regions
Add uitest option to use a real browser

When debugging ui tests it is helpful to watch the browser as the test
progresses.
Merge pull request #834 from jwalgran/topic/add-all-itree-regions

Add a migration to load all iTree regions
Make uitests more robust

  * When fetching trees from the database the queries are now scoped to
    the test instance to prevent other data in the database from
    interfering with assertions.

  * I was running into intermittent failures in some of the tests which,
    showed up more when running with a virtual display. Adding delays
    between steps appeared to resolve the issue.
Merge pull request #840 from jwalgran/fix/uitest

Make uitests more robust
Merge pull request #839 from jwalgran/topic/add-ui-test-visual-switch

Add uitest option to use a real browser