Move doxygen config to doc folder

Also removed logo_small.png and used logo.png instead

Doxyfile → doc/Doxyfile

@@ -51,14 +51,14 @@ PROJECT_BRIEF          = "Game Engine MIT"
 # pixels and the maximum width should not exceed 200 pixels. Doxygen will copy
 # the logo to the output directory.
 
-PROJECT_LOGO           = ./logo_small.png
+PROJECT_LOGO           = ../logo.png
 
 # The OUTPUT_DIRECTORY tag is used to specify the (relative or absolute) path
 # into which the generated documentation will be written. If a relative path is
 # entered, it will be relative to the location where doxygen was started. If
 # left blank the current directory will be used.
 
-OUTPUT_DIRECTORY       = ./doc/doxygen/
+OUTPUT_DIRECTORY       = ./doxygen/
 
 # If the CREATE_SUBDIRS tag is set to YES then doxygen will create 4096 sub-
 # directories (in 2 levels) under the output directory of each output format and
@@ -768,7 +768,7 @@ WARN_LOGFILE           =
 # spaces.
 # Note: If this tag is empty the current directory is searched.
 
-INPUT                  = ./core/ ./main/ ./scene/
+INPUT                  = ../core/ ../main/ ../scene/
 
 # 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