Directional Grid

This library stores up to eight directions in each cell of a two dimensional grid. It can be used to generate mazes both manually and automatically.

Differences from my obsolete Prim Grid library include:

• DG offers a direct grid2d_Grid derivative with a cleaner interface.
• Edge wrapping can be toggled at will instead of on creation/reset.
• Connections can be made manually with coordinates and/or directions rather than bits or hidden indices.
• Prim's algorithm is still provided, but whether or not the connections reciprocate can be determined within each proc call.
• Various cell categories can be identified and gathered.