Load swagger ui from `swagger-ui` package instead.

Added option `swaggerDistRoot` for specific file overrides.
Swagger 1.2 compatability. Moved strong-remoting/ext/swagger to this module.

Will now correctly return model schemas.

Moved swagger.js tests to this module.
Fix api resource path and type ref to models.
Some swagger 1.2 migration cleanup.

- Added array items definition.
- Ignored body when specified via arg.http.source.
Make sure body parameter is shown.
Refactoring swagger 1.2 rework.

Added comments, api version, and better Swagger 1.2 compat.
Refactor key translations between LDL & Swagger.

Route.accepts & route.returns can now share these translations.
Allow easy setting of accessToken in explorer UI.
Restore existing styles.

TODO extract overrides instead of replacing styles wholesale.
Fix missing strong-remoting devDependency.
Use express routes instead of modifying remoting.

This completes the migration of swagger processing from strong-remoting
into loopback-explorer.

Added additional usage instructions to README and additional testing.

This commit introduces a change into where resource descriptors
are hosted. They are no longer hosted under /swagger, but instead
under the same path as the Explorer, wherever that may be.
Generally, the resource listing will be available at
/explorer/resources, and api listings under
/explorer/resources/{modelName}.
LDL to Swagger fixes & extensions.

- Supports all three LDL array type specifications.
- Added model-helper tests.
- translate-keys no longer modifies the incoming object.
- Non-primitive types are now correctly converted into a primitive
  with a `format` attribute.
- `id` properties are not assumed to be required if they are generated.
Refactor route-helper & add tests.

- Uses model-helper to parse types for swagger.
- Separated returns & accepts hacks.
- Documentation fixes
- TODO add param regex
Rename translateKeys to translateDataTypeKeys.
Add url-join so path.join() doesn't break windows
Remove peerDependencies, use express directly.
Remove swagger.test.js license
Remove preMiddleware.

Not necessary since this can easily be done with an app.use() before
calling loopback-explorer.
More consise type tests
Simplify `accepts` and `returns` hacks.