- .msg files are PascalCase
- topics are still either per msg or explicitly listed in TOPICS
- compatible structs are still generated (eg struct msg_s), but ROS2 style px4::msg::Msg is also available
using only <px4_getopt.h> as include, cleanup related includes
added check that all the option are valid (myoptind >= argc). if there are invalid options on some script that might now lead not to run commands