Basic plants

[pahp]

Need plant action key, planting consumes a seed and starts a plant.

Plant growth rate will ultimately depend on many vars, but for now plant will raise a level every n turns and when it reaches (say) level m it will produce seeds. Maybe it has some seeds at level m-1 but not full.

If not harvested by "level" (age) m+o, the tree decays.

[pahp]

Duplicate of #14 -- thanks github app and crappy internet service.