Added new file for UAV server.
Added doxygen build instruction in main.c
Added ifndef/define/endif in config.h.in.
Refactored doxygen files descriptions.
config.h is now generated in src/.
Added file uav_server.h.
Added Doxygen header to config.h file.
Added doxygen description for macros in config.h.
Base implemntation of uav_server.{c,h}.