To reduce amount of computations on the caller side and restrict possible
values.
* verts can't be non-int because it's a number of things.
* worldsize is initially defined as int by ESM::Land::REAL_SIZE.
* Put function to calculate heightfied shift into components to be able to
reuse by other binaries.
To avoid triggering NavMesh update when RecastMesh change should not change
NavMesh.
Based on the following assumption:
Given a set of transformations and a bounding shape for all these
tranformations, a new object transformation that does not change this
bounding shape also should not change navmesh if for all of this object
transformations resulting navmesh tiles are equivalent
The idea is to report back to RecastMeshManager all changes of NavMesh if there
are any assiciated with RecastMesh version. So we know the last time when
RecastMesh change resulted into the NavMesh change. When later report shows
that there was no NavMesh change for a new RecastMesh version we can assume
that any object transformation within the same bounding box should not change
NavMesh.
