fix to make the copy constructor public again. some compilers required it
seem the std::swap default isn't good for overmap so for now duplicate code
fix max and min count checking
Make picket fence smashable
Merge pull request #248 from benjamg/hotfix/overmap_copy_constructor

fix to make the copy constructor public again. some compilers required it
use omspec before valid can be used
Merge pull request #250 from iank/smashable_picket_fence

Make picket fence smashable
Make smashing picket fences drop some 2x4s and nails instead of... spears?
Merge pull request #249 from benjamg/hotfix/highway_spawn

fix max and min count checking