Fix #1812 CSV files are no longer imported correctly when double quotes inside strings are delimited with backslashes

Fix #1788 GephiFormatException: Gephi failed saving the project. Make sure no null names are used from old project files.

Spreadsheet importer detail so usage from toolkit will be easier and automatic as before for all CSV file types.

#1562 Implement VizualizationController.selectNodes/selectEdges: Fix null pointer exception and synchronization issues with octree usage

Fix #1511 Filter is changed after saving file and opening again
Fix #1458 Filter settings incorrect and causing crashes after reloading a .gephi file

#1706 Clarify how pagerank works in the code and improve performance. Also adapt code to correctly take into account parallel edges so each neighbor is not processed several times (+ ignore self loops too).