Feature/edge(ui) (#40)

* add webview-x code

* add logic for json_escape function

* fix warning

* merge edge changes

ui/tauri-edge.cc

@@ -0,0 +1,32 @@
+#include "webview-edge.h"
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+    void wrapper_webview_free(webview_t w)
+    {
+        webview_destroy(w);
+    }
+
+    webview_t wrapper_webview_new(const char *title, const char *url, int width, int height, int resizable, int debug, webview_external_invoke_cb_t external_invoke_cb, void *userdata)
+    {
+        webview_t w = webview_create(external_invoke_cb, title, width, height, resizable, debug);
+        webview_set_userdata(w, userdata);
+        webview_navigate(w, url);
+        return w;
+    }
+
+    void *wrapper_webview_get_userdata(webview_t w)
+    {
+        return webview_get_userdata(w);
+    }
+
+    void webview_exit(webview_t w)
+    {
+        webview_terminate(w);
+    }
+
+#ifdef __cplusplus
+}
+#endif