* saving search query to undo stack with MessageSearch
* saving node and edge with name to undo stack with MessageActivateNode and MessageActivateEdge
* added FeatureController that handels distribution of MessageActivateTokens
* clearing views when refreshing or changing project
* clearing undo stack when changing project
* added StorageCache derived from StorageAccessProxy
This change switches the code view UI to use minimize and maximize buttons within the QtCodeView instead of creating
separate windows for each maximized code file. Real icons for the buttons are still missing.
* added title for snippets
* title displays name of parent scope.
* when new TokenLocationFiles are created in the storage they are now returned as shared_ptr to ensure correct linking in the contained data.
* Storage::getTokenLocationsForLinesInFile() now always returns pairs of start and end locations.
* Adjusted code snippet view to regard the change described above.
* 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).
Having only one access point to the Storage will simplify caching and parallelisation in the future. Also the two
accesses were never really independent of each other anyways, because in some cases they had to access both data sets.