Core/Dependencies: Clean up recastnavigation folder

Remove old files from recastnavigation folder and update the structure to the same of https://github.com/memononen/recastnavigation/ to allow easier updates.

src/server/scripts/CMakeLists.txt

@@ -47,7 +47,9 @@ message("")
 include_directories(
   ${CMAKE_BINARY_DIR}
   ${CMAKE_SOURCE_DIR}/dep/recastnavigation/Detour
+  ${CMAKE_SOURCE_DIR}/dep/recastnavigation/Detour/Include
   ${CMAKE_SOURCE_DIR}/dep/recastnavigation/Recast
+  ${CMAKE_SOURCE_DIR}/dep/recastnavigation/Recast/Include
   ${CMAKE_SOURCE_DIR}/dep/g3dlite/include
   ${CMAKE_SOURCE_DIR}/dep/SFMT
   ${CMAKE_SOURCE_DIR}/dep/zlib