add ResourceExistsPropertyDefiner
Introducing AbstractDiscriminator base class to avoid repeated start()/stop() implementation in each concrete Discriminator
next version will be 1.1.0
Merge pull request #57 from xuhuisheng/master

add ResourceExistsPropertyDefiner
Merge pull request #87 from nurkiewicz/abstract-discriminator

Introducing AbstractDiscriminator base class
added ResourceExistsPropertyDefiner, doc update
use native int for backlog property
use native int for backlog property
doc comment correction
added private modifier to mutable fields
added static and final modifier to PreSerializationTransformer field

The LoggingEventPreSerializationTransformer is completely stateless and
therefore inherently thread-safe.  Therefore, there is no reason to
create a distinct instance for each appender.  Moreover, once created it
never needs to be modified, therefore it should be properly marked as
immutable via the final keyword.
marked SocketAppender convenience constructors as deprecated

Convenience constructors that are used to set mutable fields that have
proper accessors add little value, and they make it more complicated to
subclass.  Best practice is to use constructor arguments only to
initialize fields that are immutable or for which an accessor method
cannot be safely provided within the design constraints of the class.

The only use of these constructors by logback modules is in the
SocketMin class.  However, because these constructors were exposed as
API (public modifier) there is a chance that other code is using them,
therefore marking them as deprecated rather than removing them.
fixed deprecation warning for SocketAppender convenience constructor
marked SSLSocketAppender convenience constructors as deprecated

For consistency with SocketAppender.
removed unused SocketReceiver.createExecutorService
use "receiver" instead of "remote" in receiver diagnostic messages
marked SocketAppender convenience constructors in access as deprecated

For consistency with logback-core.
moved MockContext and MockExecutorService to ..core.net.mock
added missing doc comments to MockExecutorService
fixed references to MockContext in test classes