Templatetag return empty string on None input

fixes #463 on github
Fix street view css
Add test utility
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