Use README.md as the documentation main page

Doxyfile

@@ -992,7 +992,8 @@ WARN_LOGFILE           =
 # Note: If this tag is empty the current directory is searched.
 
 INPUT                  = vst.h \
-                         vst.hpp
+                         vst.hpp \
+                         README.md
 
 # This tag can be used to specify the character encoding of the source files
 # that Doxygen parses. Internally Doxygen uses the UTF-8 encoding. Doxygen uses
@@ -1207,7 +1208,7 @@ FILTER_SOURCE_PATTERNS =
 # (index.html). This can be useful if you have a project on for instance GitHub
 # and want to reuse the introduction page also for the Doxygen output.
 
-USE_MDFILE_AS_MAINPAGE =
+USE_MDFILE_AS_MAINPAGE = README.md
 
 # If the IMPLICIT_DIR_DOCS tag is set to YES, any README.md file found in sub-
 # directories of the project's root, is used as the documentation for that sub-