* Fixes for many low-severity compiler warnings
Mostly a lot of pedantic things like end-of-file newlines and commas on the last enum value. However some fixes like the weak v-tables warnings fixes might help with code gen. It's unclear if the linker is able to elide multiple copies of the same type's v-table in different translation units, (sometimes it can) but these fixes ensure we don't have to rely on it.
dtNavMeshQuery now fails initialization if too many nodes are requested
in the node pool. This could cause wrong paths and infinite loops to
happen if the node indices started overflowing dtNodeIndex or
dtNode::pidx.
Fix#178
* Added virtual qualifier to a few destructors in subclasses.
* Removed a few empty destructors that didn't need to be explicitly defined.
* Fixed a few typos
* Removed unnecessary empty virtual destructors in some classes with parent's who derrived from a class with a virtual destructor
The new code assigns several (consecutive) dtNodes for polygons that lie on tile boundary. Each node gets its own point. since the nodes are packed together consecutively, it is easy to find the right node by reference even though there are several.
