Creates a rotation matrix.
// Translate, rotate and scale a mesh. Try varying
    // the parameters in the inspector while running
    // to see the effect they have.
using UnityEngine;
using System.Collections;
public class ExampleClass : MonoBehaviour {
    public Vector3 eulerAngles;
    private MeshFilter mf;
    private Vector3[] origVerts;
    private Vector3[] newVerts;
    void Start() {
        mf = GetComponent<MeshFilter>();
        origVerts = mf.mesh.vertices;
        newVerts = new Vector3[origVerts.Length];
    }
    void Update() {
        Quaternion rotation = Quaternion.Euler(eulerAngles.x, eulerAngles.y, eulerAngles.z);
        Matrix4x4 m = Matrix4x4.Rotate(rotation);
        int i = 0;
        while (i < origVerts.Length) {
            newVerts[i] = m.MultiplyPoint3x4(origVerts[i]);
            i++;
        }
        mf.mesh.vertices = newVerts;
    }
}