Make core/ includes absolute, remove subfolders from include path

This allows more consistency in the manner we include core headers,
where previously there would be a mix of absolute, relative and
include path-dependent includes.

platform/javascript/api/api.cpp

@@ -29,7 +29,7 @@
 /*************************************************************************/
 
 #include "api.h"
-#include "engine.h"
+#include "core/engine.h"
 #include "javascript_eval.h"
 
 static JavaScript *javascript_eval;

platform/javascript/api/javascript_eval.h

@@ -31,7 +31,7 @@
 #ifndef JAVASCRIPT_EVAL_H
 #define JAVASCRIPT_EVAL_H
 
-#include "object.h"
+#include "core/object.h"
 
 class JavaScript : public Object {
 private:

platform/javascript/dom_keys.inc

@@ -28,7 +28,7 @@
 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
 /*************************************************************************/
 
-#include "os/keyboard.h"
+#include "core/os/keyboard.h"
 
 // https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/keyCode#Constants_for_keyCode_value
 #define DOM_VK_CANCEL 0x03

platform/javascript/export/export.cpp

@@ -28,9 +28,9 @@
 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
 /*************************************************************************/
 
+#include "core/io/zip_io.h"
 #include "editor/editor_node.h"
 #include "editor_export.h"
-#include "io/zip_io.h"
 #include "main/splash.gen.h"
 #include "platform/javascript/logo.gen.h"
 #include "platform/javascript/run_icon.gen.h"

platform/javascript/http_client_javascript.cpp

@@ -28,8 +28,8 @@
 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
 /*************************************************************************/
 
+#include "core/io/http_client.h"
 #include "http_request.h"
-#include "io/http_client.h"
 
 Error HTTPClient::connect_to_host(const String &p_host, int p_port, bool p_ssl, bool p_verify_host) {
 

platform/javascript/javascript_main.cpp

@@ -28,7 +28,7 @@
 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
 /*************************************************************************/
 
-#include "io/resource_loader.h"
+#include "core/io/resource_loader.h"
 #include "main/main.h"
 #include "os_javascript.h"
 

platform/javascript/os_javascript.cpp

@@ -30,9 +30,9 @@
 
 #include "os_javascript.h"
 
+#include "core/io/file_access_buffered_fa.h"
 #include "gles2/rasterizer_gles2.h"
 #include "gles3/rasterizer_gles3.h"
-#include "io/file_access_buffered_fa.h"
 #include "main/main.h"
 #include "servers/visual/visual_server_raster.h"
 #include "unix/dir_access_unix.h"