Actually add Doxygen main page

ShadowNinja · ShadowNinja · commit 711808343db6 · 2016-01-09T15:11:43.000-05:00
I apparently forgot to add this file in my previous commit (bd40ee2).
diff --git a/doc/main_page.dox b/doc/main_page.dox
@@ -0,0 +1,8 @@
+/** @mainpage The Minetest engine internal documentation
+
+Welcome to the Minetest engine Doxygen documentation site!\n
+This page documents the internal structure of the Minetest engine's C++ code.\n
+Use the tree view at the left to navigate.
+
+*/
+
