Fixes#519
Introduces some internal changes to the framework allowing the use
of other types than MessageChannel/SubscribableChannel as bindable
types (e.g. Flux, Observable, KStream, etc.)
- Modify BinderFactory to allow the retrieval and lookup of a
binder not only by name, but also by binding target type
- Subsequent changes to ChannelBindingService and tests to account
for the modified signature
- Introduce BindingTargetFactory as the contract for creating bound
elements
- Remove any references to chanels and bound elements and use
'binding target' systematically across the board
Reinstate our own Checkstyle checks with a reduced set of rules so that header
validation can be performed automatically at compile time.
Use ${project.version} for the checkstyle plugin configuration
Renaming some occurences of 'boundElement' to 'bindingTarget'
Renamed a stray occurence of 'channel'
Fix some occurences of String concatenation in the same line after reformatting
