Mexico graphic updates

Last update 18/11/02: addons by Legends of '67 v 1.1 !!!

Track is updated with addons by Legends of '67, Darkgreen and sky/horyzon by Alan Heeley.
1-copy files from Lo67_Mexico_v1.1.zip, downloadable from Legends of '67.
2-copy files from mexico.zip, downloadable from HERE in original dir.
3-copy files from alskies_mexico_v1.0.zip, downloadable from HERE.