Allow people to be in more than one region

[JB62]

Currently, people are N (north) C (central) or S (south), but we have a number or people that operate from N or S (staying with GF etc). We also have a largish number of people in the central region that could conceivably be regarded as being N or S. For slot claim purposes, people should be able to be in more than one region, so suggest the current region field be replaced by a series of check boxes for N C and S so that they can be in any region.