UV: Set error status on connect failure

Change-Id: Ic663d241d2ab1852310c4c238060320b3269f3d9
Libev: Also check for include/libev

Change-Id: Ie1b2d9a1d902b6033f3cd977a2e0c07c72d0c033
CCBC-152: Allow to check for existence of a key

This adds a new version to the observe command structure which allows to
specify that the request be made to the master only.

Change-Id: I96debd0a14586c0a0578b968759d92b3420a0ac7
Add keystats (WIP)

Change-Id: I4dac61bb232a93200bd3e6ec4af9b12b319645dc