Allow spatial blocking

[TeunHuijben]

For the enormous datasets, make an input parameter that allows for only loading a small spatial chunk of the data

[TeunHuijben]

Related to #46

[TeunHuijben]

Related to #72,

#72 adds the option of coordinate_filters, to only show a smaller xyz block of data. Problem is that still the entire database is queried every time, which makes it still slow (tracksdata/spatialgraph will help here in the future)