LogstashLayout: enabling contextmap to the underlying formatter
LogstashLayout: enabling contextmap to the underlying formatter
Merge pull request #41 from branch 'master' of git://github.com/brndkfr/logstash-logback-encoder into brndkfr_master

Conflicts:
	src/main/java/net/logstash/logback/layout/LogstashLayout.java
Merge branch 'brndkfr_master' into master