[20170404185653] General Improvements

[ddollar]

CLI Changes

• convox install no longer logs logs directly into the Rack but instead prints connection information

Fixes

• Creation of an app’s ELB only use TCP listeners

Pull Requests

• #2073 Print a message instead of logging into Rack after install [@soulshake]
• #2103 Add GitHub pull request template [@ianmalott]
• #2117 Quick fixes [@MiguelMoll]
• #2118 convox.agent and elb-udp fix [@spencerhakim]