Improvements
* Changelog added
* CI integration improvements
* add ArduPilotCapabilities abstraction to get SITL binary information
* gdb and valgrind integration
* SITL instance-number and speedup options
* add option to preserve state between runs
* add option for defaults-filepath
* add option to specify a path to a SITL_BINARY to run in environment (and its SITL_DEFAULTS_FILEPATH)
Cleanup
Bug Fixes