Add Travis configuration

Change-Id: I8ccabf783ae4c580f01dd078a47cdbce7fb8311f
Select Ruby for Travis from .travis.yml

Change-Id: Ibcb52a5aeb40375a6145c6f0f366a028499b9d26
Stop periodic timers when evacuating.

The periodic timers set up to send dea.heartbeat and dea.advertise
signals are cancelled at the beginning of the evacuation.

This prevents the interference of heartbeat and advertise messages
with the evacuation process.

Change-Id: Ic49612f08422d81abcd44ab4efe64cbc5235eb01