PX4 Release 1.6.0 RC1

By January 30, 2017 May 4th, 2017 PX4 Release

For full details see PX4 Release 1.6.0 RC1 (Github)

This is a release candidate for the current beta branch, nominally tagged as 1.6.0. We will likely conclude to skip 1.6-1.9 in favour of releasing a 2.0.0 in a couple weeks, so consider this release candidate a reasonably well tested snapshot (hence the RC naming) of the current development and not a preview for the next stable release.