ui: snippet sizes

* added SnippetMerger class that conducts the merging and snapping of TokenLocations to create snippets.
* added parameters for snippet snapping and merging to ApplicationSettings.
* added forEachStartTokenLocation() and forEachEndTokenLocation() to TokenLocationLine and TokenLocationFile.
* added < and > operators to TokenLocation that compare the location part (not the id).

src/lib/data/access/StorageAccessProxy.h

@@ -34,6 +34,8 @@ public:
 
 	virtual TokenLocationCollection getErrorTokenLocations(std::vector<std::string>* errorMessages) const;
 
+	virtual std::shared_ptr<TokenLocationFile> getTokenLocationOfParentScope(const TokenLocation* child) const;
+
 private:
 	StorageAccess* m_subject;
 };