dispersal happens last

[goldingn]

In the deterministic analysis of dynamics with dispersal transitions, the dispersals always occur after the other transitions (e.g. dispersing individuals are always subject to home-patch mortality, not new-patch mortality). This does not happen with the stochastic case.

Deterministic dispersals (i.e. building transition matrices) should either happen in turn, or pop::dynamic() should always put them last, and reflect this in the documentation.

If going for the former, could be done in conjunction with #31 to speed up Matrix construction