Add Doxygen support

.gitignore

@@ -4,3 +4,6 @@ Build
 DerivedDataCache
 Intermediate
 Saved
+
+# Other
+Doxygen

Doxyfile

@@ -0,0 +1,38 @@
+PROJECT_NAME            =  "CARLA UE4 Plugin"
+OUTPUT_DIRECTORY        =  Doxygen
+CREATE_SUBDIRS          =  YES
+FULL_PATH_NAMES         =  NO
+JAVADOC_AUTOBRIEF       =  YES
+LOOKUP_CACHE_SIZE       =  3
+EXTRACT_ALL             =  YES
+EXTRACT_PRIVATE         =  YES
+EXTRACT_STATIC          =  YES
+CASE_SENSE_NAMES        =  YES
+SORT_BRIEF_DOCS         =  YES
+WARN_IF_UNDOCUMENTED    =  NO
+WARN_LOGFILE            =  Doxygen/warnings.log
+INPUT                   =  Source
+FILE_PATTERNS           =  *.cpp *.h *.hpp *.cc
+RECURSIVE               =  YES
+SOURCE_BROWSER          =  YES
+STRIP_CODE_COMMENTS     =  NO
+REFERENCED_BY_RELATION  =  YES
+REFERENCES_RELATION     =  YES
+ALPHABETICAL_INDEX      =  NO
+HTML_DYNAMIC_SECTIONS   =  YES
+DISABLE_INDEX           =  YES
+GENERATE_TREEVIEW       =  NO
+FORMULA_FONTSIZE        =  12
+GENERATE_LATEX          =  NO
+MACRO_EXPANSION         =  YES
+EXPAND_ONLY_PREDEF      =  YES
+INCLUDE_PATH            =  "Source/Carla" "Source/Common" "Source/CarlaServer/source"
+INCLUDE_FILE_PATTERNS   =  *.h *.hpp
+HIDE_UNDOC_RELATIONS    =  NO
+HAVE_DOT                =  YES
+TEMPLATE_RELATIONS      =  YES
+CALL_GRAPH              =  YES
+CALLER_GRAPH            =  YES
+DOT_IMAGE_FORMAT        =  svg
+INTERACTIVE_SVG         =  YES
+DOT_MULTI_TARGETS       =  YES