Templatetag return empty string on None input

fixes #463 on github
Misc admin site support
Merge pull request #465 from steventlamb/bug/float_template_crash

Templatetag return empty string on None input
Merge pull request #466 from RickMohr/misc-admin-support

Misc admin site support
Merge pull request #470 from maurizi/master

Misc fixes
Fix typos in fieldHelpers.js, fixes #367
Fix responsive styling bugs, strip out unneeded styling from plot detail partial
Don't serialize null values when adding plots/tress, fixes # 453
Enter edit mode based on location hash

Going to a plot detail page with "#edit" will automatically trigger
editing.
Merge pull request #475 from ahinz/fix/393/enter-edit-mode-based-on-location-hash

Enter edit mode based on location hash
Alias total trees in blocktrans, fixes #338
Merge pull request #473 from maurizi/fix/species

Fix typos in fieldHelpers.js, fixes #367
Merge pull request #474 from maurizi/fix/addTree

Don't serialize null values when adding plots/tress, fixes # 453
Merge pull request #476 from maurizi/fix/total

Alias total trees in blocktrans, fixes #338
Disallow editing when no fields are editable

fixes #376 on github

Default the 'Edit' button to be disabled with explanatory title text. on js initialization, search the DOM for edit fields, which are only present when fields are in fact editable, and if they exist, re-enable the 'Edit' button.
Merge pull request #469 from steventlamb/bug/376_disallow_editing

Disallow editing when no fields are editable
Fix image upload progress bar
Merge pull request #480 from RickMohr/image-upload-progress-bar

Fix image upload progress bar
Require login and use regular urls.

Fixes #339 and Fixes #393

When editing plots and trees use normal URLs (i.e. /inst/plot/349/edit)
instead of hashes.
Merge pull request #481 from ahinz/fix/339/login-required

Require login and use regular urls.