v0.6.16

Changelog:

29ca669 Update release channel categorization
a264cc2 Fix profile deadlock.
ce192c7 Add special release channel
9da5ff8 Adapt updatemgr to new release channel handling
2127f1b Reload indexes when restarting with portmaster-start
642e2eb Establish beta and staging release channels, move indexes to helper
8a46e78 Fail update check when the updating indexes fails