Build

Add start of nbuild tool. #442

Job	Run time
binaries (thumbv6m-none-eabi, 0x0802_0000)	25s
linux-libraries	19s
run-tests	10s
binaries (thumbv6m-none-eabi, 0x1002_0000)	22s
binaries (thumbv7em-none-eabi, 0x0802_0000)	38s
binaries (thumbv7em-none-eabi, 0x1002_0000)	34s
windows-libraries	2m 7s
binaries (thumbv8m.main-none-eabi, 0x0802_0000)	24s
binaries (thumbv8m.main-none-eabi, 0x1002_0000)	23s
release	0s
	5m 22s

Provide feedback