Simplify hip meshes

- Import STL file in Blender
- Run Limited Dissolve with a max. angle of 5d, using normals
- Export STL file from Blender

Before:

```console
$ du -hs LeftHip*
13M	LeftHipPitch.stl
9.9M	LeftHipRoll.stl
4.5M	LeftHipYaw.stl
```

After:

```console
$ du -hs LeftHip*
7.9M	LeftHipPitch.stl
6.6M	LeftHipRoll.stl
2.9M	LeftHipYaw.stl
```

Fixes #2

Author: stephane-caron