Run unused functions reported by cppcheck
This change removes a few (but not all) unused functions.
Some unused helper functions were not removed due to their complexity and potential of future use.
Games often and increasingly do not use this mapgen alias, as it
is only required for Mapgen V6. Such games were triggering the
recently added error message.
Even if this mapgen alias was defined, dirt nodes placed under a
wide trunk were inconsistent with biomes that do not use dirt
surface nodes.
Place trunk nodes below a wide trunk instead of 'mapgen_dirt'.
On sloping ground, the trunk then extends down to the surface,
instead of the surface rising up to meet the trunk. This looks
more natural and does not alter the terrain.
ServerEnvironment is a huge class with many accessors. In various places it's not needed
Remove it to reduce the ServerEnvironment view.
Idea here is to reduce size of some of our objects to transport lightweight managers and permit easier testing
Pathfinder is now tied to a generic map, not a ServerMap, it can be
ported to client
* Rename IWritableNodeDefManager to NodeDefManager
* Make INodeDefManager functions const
* Use "const *NodeDefManager" instead of "*INodeDefManager"
* Remove unused INodeDefManager class
* Merge NodeDefManager and CNodeDefManager
* Document NodeDefManager
