Fix UninitializedFieldError when using RedisScalatraBroadcasterConfig

Forgot that I hadn't pushed this particular commit when issuing the pull request.

Overriding the trait `def`s using `val` in an extending class doesn't work, so I
needed to change it to `def` in the `RedisScalatraBroadcasterConfig` class.
improve error message when no Get route is defined
while using the AtmosphereSupport (this isn't supposed to happen, but
if it does it saves you some time)
Merge pull request #365 from lloydmeta/fix/RedisBroadcastConfig

Fix UninitializedFieldError when using RedisScalatraBroadcasterConfig
Merge pull request #366 from backuitist/2.2.x

improve error message when no Get route is defined while using AtmosphereSupport
update release notes
minor reformat in release notes
Fix NPE in AtmosphereClient when looking up an unknown broadcaster
Merge pull request #369 from backuitist/atmosphere-lookup-npe

Fix NPE in AtmosphereClient when looking up an unknown broadcaster
simplify TrackMessageSizeInterceptor configuration
Merge pull request #370 from backuitist/atmosphere-tracking-size

simplify TrackMessageSizeInterceptor configuration
readme tweak
Log when request body parsing fails and make eager json parsing configurable
use charset from request to decode the json input stream
publish 2.3.0.RC1
go to snapshot again
Remove unused Shapeless reference
Merge pull request #383 from ceedubs/rm-shapeless

Remove unused Shapeless reference
Fix issue #385: If a ScalatraFilter extends the ScalatraAsyncSupport trait, the filter setAsyncSupport is called
Merge pull request #386 from jenshaase/2.3.x_2.10

Fix issue #385: ScalatraFilter with ScalatraAsyncSupport
Update ScentrySupport to avoid compiler warnings

Overriding configureScentry and registerAuthStrategies methods cause "side-effecting nullary method" or "non-nullary method overrides nullary method" warnings depending on whether we omit parenthesis or not.
With this simple update that issue can be avoided without breaking backwards compatibility.