Treat all compile warnings as errors
Fix Android compile failure: st_mtim, UTIME_OMIT

Use utimes(2) instead of utimensat(2), use struct timeval instead of
struct timespec

Add strbuf helper functions for struct timeval and time_ms_t
Track most recent ack from neighbours, prevent duplicate broadcast packets
Use routing table to check if a node is unreachable
Minor refactoring
Refactoring towards supporting new network simulator
Create new AF_UNIX based network simulator
Use simulator for existing msp tests
Improve tests using simulator features
Improve routing tests: simulator daemon control

Improve fifo (named pipe) handling
Use executeOk --error-on-fail to run simulator daemon
Collect and log simulator daemon's stdout and stderr
Orderly shutdown of simulator daemon in finally_xxx() functions, not
teardown_xxx()
Ensure simulator is still running
Log simulator traffic stats