Add license header to all files, and bump version number to 0.8.4_alpha.1

src/App.hpp

@@ -1,3 +1,23 @@
+/* SampleHive
+ * Copyright (C) 2021  Apoorv Singh
+ * A simple, modern audio sample browser/manager for GNU/Linux.
+ *
+ * This file is a part of SampleHive
+ *
+ * SampleHive is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
 #pragma once
 
 #include <wx/app.h>