Corrige avertissement de la variable globale player_api

- Teste l'existence de la variable globale player_api avant de la lire
- Ajoute un message de chargement du mod dans le journal "action"

init.lua

@@ -9,7 +9,7 @@ local BONE_POSITION, BONE_ROTATION = (function()
 	return dofile(modpath .. "/model.lua")
 end)()
 
-local get_animation = player_api and player_api.get_animation or default.player_get_animation
+local get_animation = minetest.global_exists("player_api") and player_api.get_animation or default.player_get_animation
 if not get_animation then
 	error("player_api.get_animation or default.player_get_animation is not found")
 end
@@ -299,3 +299,5 @@ minetest.register_globalstep(function(dtime)
 		animate_player(player, dtime)
 	end
 end)
+
+minetest.log("action", "[playeranim] loaded.")