Fixed memory allocation in detail mesh and memcpy in polymesh copy
Fix for issue #38 and improvements to detail mesh tessellation

- do circumCircle calculations relative to first vertex for adde
precision
- improved the results of triangulateHull(), produces less degen
triangles
- fixed case with contour merging when outline is null
Merge branch 'master' of https://github.com/memononen/recastnavigation into trinitycore