Fixed  configuration options of FailedThresholdCallback could not be invoke when the value less then three.  (#161)

# Conflicts:
#	build/version.props
#	samples/Sample.Kafka.MySql/Sample.Kafka.MySql.csproj
#	samples/Sample.RabbitMQ.MySql/AppDbContext.cs
#	samples/Sample.RabbitMQ.MySql/Program.cs
#	samples/Sample.RabbitMQ.MySql/Sample.RabbitMQ.MySql.csproj
#	src/DotNetCore.CAP/LoggerExtensions.cs

* fixed message enqueue exception in v2.2

* add log to samples

* Improved log output.  #114

* add default timeout configuration for kafka client.

* fixed retry processor bugs.

* Fixed kafka producer exception log without logging when publish message.

* update version num to 2.2.2

* rename configuration options FailedCallback to FailedThresholdCallback

* rename files name.

* remove unused files.

* modify the error comments.

* update samples.

* add logs.