Added xatlas as alternative to thekla, forced it on.

Did some hacks to it to avoid it from failing on bad geometry.

modules/thekla_unwrap/config.py

@@ -1,5 +1,6 @@
 def can_build(env, platform):
-    return (env['tools'] and platform not in ["android", "ios"])
+    #return (env['tools'] and platform not in ["android", "ios"])
+    return False
 
 def configure(env):
     pass