solidify meshes,

add blend files,
fix spawn positions,
add materials

Assets/models/enemy.mtl

@@ -0,0 +1,12 @@
+# Blender MTL File: 'enemy.blend'
+# Material Count: 1
+
+newmtl Material
+Ns 323.999994
+Ka 1.000000 1.000000 1.000000
+Kd 0.800000 0.800000 0.800000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.000000
+Ni 1.450000
+d 1.000000
+illum 2