arm.blend,arm.blend1 and arm.blend2 deleted, leftArm.blend and rightArm.blend created:

- Realized the blend# files were autosave files, so I deleted them.
- The mesh for the left arm contained a right arm, mistake solved
  by making leftArm and rightArm (rightArm will be used later to make
  weapons arms).
- Shoulder in both meshes no longer exists since they wouldn't appear
  ingame.
- Meshes now have Materials.
Merge branch 'Grupo-A' of https://github.com/eloipuertas/ES2013Dimarts into Grupo-A