Blender Git Loki

GPencil: Fix unreported performance issue with relative onion mode

When the relative mode was used, the calculation of the total number of vertices was not done and it was using the total number of vertices in the datablock. This worked for small files, but with complex files the time to allocate all the data was too long and the performance was very bad.

Now, for relative mode the real number of vertex is calculated.

Also fixed the same problem when onion and multiedit is enabled.