* brush format is preference for [maptypes, brushtypes]: [mapq1, quake], [mapq2, quake2], [mapq3, quake3]:
preferences->Brush->Brush type: Axial projection, Brush primitives, Valve 220
* autodetect brush type on map opening
* brush face surfaceflags are optional on loading for flexibility
* 'Snap planes to integer grid' option is always off by default
0b3f42ffbc