Use "pragma max_page_count" to define max allowed file size in combination with
"pragma page_size" based on a new setting "max navmeshdb file size".
* Stop navmeshtool on the first db error.
* Disable writes to db in the engine on first "database or disk is full"
SQLite3 error. There is no special error code for this error.
* Change default "write to navmeshdb" to true.
* Use time intervals for transaction duration instead of number of changes.
Use LRU modification to hold currently used items. Use RecastMesh binary
data for item key.
Store original pointer of btCollisionShape in user pointer to make available
it as an identifier within all duplicates. Use pointer to heights data array
for btHeightfieldTerrainShape.
