Merge pull request #293 from ahinz/fix/134/nested-tree-urls

Allow accessing tree via nested urls. Fixes #134.
Merge pull request #305 from ahinz/fix/tests

Fix/tests
Fix javascript lint
Add baconutils to gruntfile
Merge pull request #308 from ahinz/fix/261/fix-update-tree-with-empty-number-fields

Serialize empty numbers as nulls. Fixes #261.
Merge pull request #307 from ahinz/fix/267/link-otm-logo-to-last-viewed-map-page

Link otm logo to last viewed map page
Merge pull request #301 from ahinz/fix/254/json-from-request

Tests pass without this shim. Fixes 254.
Catch/process tree photo validation errors. Fixes #298.

Currently a redirect happens to the plot detail page with the error as a
query string param. We could try to inject it directly but that seems
suboptimal.