Convert wrapping from boolean to enum

[docwhomc]

Switch from specifying border wrapping with a boolean—true for wrapping (toroidal for rectangular world shape) and false for non-wrapping border—to an enum—specifically the same enum used for the shape since the wrapping options are shape dependent.

[docwhomc]

See more-shapes branch.

[docwhomc]

Builds on #1.

[docwhomc]

95411c6 Use Shape to store wrap setting, add cylindrical

Incorporate border wrapping into the Shape enum, using TOROIDAL and WRAPPED_ELLIPTIC for the wrapped versions of RECTANGULAR and ELLIPTIC, respectively. Also add CYLINDRICAL so worlds with rectangular borders can be wrapped in x, but not z.

[docwhomc]

In pre-release version 2.0.0-dev-20w29a.