Reduced coupling by extracting an interface from the StateFlowGraph
Improved locking system of the SFG
Refactoring StateVertex so it can become an interface
Extracted an interface out of StateVertex
Added missing file
Merge remote-tracking branch 'origin/master' into clean-up

Conflicts:
	core/src/main/java/com/crawljax/condition/CountCondition.java
	core/src/main/java/com/crawljax/condition/JavaScriptCondition.java
	core/src/main/java/com/crawljax/condition/NotRegexCondition.java
	core/src/main/java/com/crawljax/condition/NotUrlCondition.java
	core/src/main/java/com/crawljax/condition/NotVisibleCondition.java
	core/src/main/java/com/crawljax/condition/NotXPathCondition.java
	core/src/main/java/com/crawljax/condition/RegexCondition.java
	core/src/main/java/com/crawljax/condition/UrlCondition.java
	core/src/main/java/com/crawljax/condition/VisibleCondition.java
	core/src/main/java/com/crawljax/condition/XPathCondition.java
	core/src/main/java/com/crawljax/core/state/StateFlowGraph.java
	core/src/main/java/com/crawljax/core/state/StateVertex.java
	core/src/test/java/com/crawljax/core/state/StateFlowGraphTest.java
	plugins/crawloverview-plugin/src/main/java/com/crawljax/plugins/crawloverview/CrawlOverview.java
Merge branch 'master' into clean-up

Conflicts:
	core/src/test/java/com/crawljax/core/CrawlerTest.java
Restored the getAllPossiblePaths
Merge pull request #279 from crawljax/clean-up

Reduce coupling