Implement LVGL with SDL for simulator (#16)

* Implemented LVGL with SDL for simulator

* cleanup

* added SDL to build

* build fix

* mutex fixes

* sim app cleanup and improvements

* docs updated

* fix for sdl?

* fix for SDL cmake setup

tactility-core/src/pubsub.c

@@ -19,7 +19,7 @@ struct PubSub {
 PubSub* tt_pubsub_alloc() {
     PubSub* pubsub = malloc(sizeof(PubSub));
 
-    pubsub->mutex = tt_mutex_alloc(MutexTypeRecursive);
+    pubsub->mutex = tt_mutex_alloc(MutexTypeNormal);
     tt_assert(pubsub->mutex);
 
     PubSubSubscriptionList_init(pubsub->items);