After Vagrant setup, recommend testing in browser

The curl command seems to throw some volunteers for a loop. The output
of curl does not make the next step obvious and even with instruction,
people sometimes run the command inside the VM.
Remove note about starting Django, node manually

We recommend the use of foreman start earlier in the documentation, so
this should be unnecessary.
Create new "Developing with Vagrant" doc section
Remove unused settings
Remove unneeded flash resources
Modify external link display
Make the 'submit a demo' link  a basic link, not a button
Add docs about creating or importing wiki pages
Fix #1898: Remove external_signup flag and feature
Update whitespace indentiation within stylus
Avoid using jQuery when not needed
Remove dead dashboards.css file
Remove waffles no longer used
Minor JS formatting for consistency
Merge pull request #2232 from darkwing/docs-waffle-update

Remove waffles no longer used
Merge pull request #2221 from openjck/vagrant-doc-improvements

Improve Vagrant installation instructions
Another image crush
Merge pull request #2234 from darkwing/another-image-crush

Another image crush
Merge pull request #2225 from darkwing/profile-demo-link

Make the 'submit a demo' link  a basic link, not a button
Merge pull request #2233 from darkwing/minor-js-formatting

Minor JS formatting for consistency