lua: start to add Lua interface

lv_core/group_parent.patch

+diff --git a/lv_core/lv_obj.c b/lv_core/lv_obj.c
+index bb4cecb..8ae35ca 100644
+--- a/lv_core/lv_obj.c
++++ b/lv_core/lv_obj.c
+@@ -1202,7 +1202,18 @@ lv_style_t * lv_obj_get_style(lv_obj_t * obj)
+         while(par) {
+             if(par->style_p) {
+                 if(par->style_p->glass == 0) {
++#if USE_LV_GROUP == 0
+                     style_act = par->style_p;
++#else
++                    /*Is a parent is focused then use then focused style*/
++                    lv_group_t *g = lv_obj_get_group(par);
++                    if(lv_group_get_focused(g) == par) {
++                        style_act = lv_group_mod_style(g, par->style_p);
++                    } else {
++                        style_act = par->style_p;
++                    }
++#endif
++
+                     break;
+                 }
+             }

lv_core/lv_lua.h

+/**
+ * @file lv_lua.h
+ *
+ */
+
+#ifndef LV_LUA_H
+#define LV_LUA_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*********************
+ *      INCLUDES
+ *********************/
+#include "../../lv_conf.h"
+#if LV_BUILD_LUA
+
+#include "lua.h"
+#include "lualib.h"
+#include "lauxlib.h"
+
+/*********************
+ *      DEFINES
+ *********************/
+
+/**********************
+ *      TYPEDEFS
+ **********************/
+
+/**********************
+ * GLOBAL PROTOTYPES
+ **********************/
+void lv_lua_set_context(lua_State *L);
+
+lua_State * lv_lua_get_context(void);
+
+void lv_lua_register(void);
+
+void lv_lua_register_function(void * c_func, const char * lua_name);
+
+void lv_lua_register_const(int num, const char * lua_name);
+
+void lv_lua_register_pointer(void * p, const char * lua_name);
+
+/**********************
+ *      MACROS
+ **********************/
+#endif
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif /*LV_LUA_H*/