introduce thread pool
Merge branch 'master' of github.com:Eernie/jbehave-rest-runner

Conflicts:
	src/main/java/nl/finan/jbehave/entities/RunningStories.java
	src/main/java/nl/finan/jbehave/rest/RunStories.java
	src/main/java/nl/finan/jbehave/rest/RunnerResources.java
	src/main/java/nl/finan/jbehave/rest/embeder/WebStoryReporter.java