XDJ-RX3: Handle / correct wrong Beatgridding at Runtime like with hotcuepoints

Since in my taste the automatic beatgridding analyzation algorithm is not as good compared to traktor, it is connected to lot of effort for the user, if she or he is supposed to beatgid Gigabytes of Tracks by hand before the DJing could really start. Even for that case in Traktor you are able to correct the beatgrid on the fly and at runtime. This can be done for example starting with the first grid and correcting this one like exactly it is done with hot cuepoints approach. Then the beatgrid sorts itself along the new set first one, as for 80% of the cases, the track is linear in its tempo so your are good to go. Then of course the new setting has to be persisted to the collection, like exactly hot cuepoints