Remove Leaflet from bower dependencies

- Leaflet cannot currently be used as a bower dep:
  bower package does not include built lib
Update demo docs:

- Include link to jsFiddle sandbox
- Link to demo docs from usage docs
Fix config.setApiSecret reference error
AMD example: fix jQuery path (for using jquery <2.0)
Grunt: run bower update on AMD demo
Update version to 0.3.7