Mynewt 1.8.0

[szymon-czapracki]

@ncasaril FYI

[ncasaril]

@szymon-czapracki, would those packages that today use newtmgr have to change to use smp? For instance:

• sys/uwbcfg
• mgmt/bcast_ota
• lib/nmgr_uwb
• lib/nmgr_cmds

Also, have a look at the apps/ directories as well please. There's another branch here that has done some work in the correct direction for the apps.

[ncasaril]

This only fails because the travis build assumes mynewt 1.7.