New Pull Request command: /touch

[Erik Joelsson]

The Skara pull request bot now accepts a new pull request command 
"/touch" (alias "/keepalive") [1]. Issuing this command will trigger a 
bot re-evaluation of a PR in its current state, which can be useful if 
something has gone wrong. More importantly, this will also reset the 
inactivity timer for the automatic closing of pull requests. While there 
are other ways to reset the timer, such as adding a comment, this new 
method will not trigger any emails and is the recommended way going forward.

/Erik

[1] 
https://wiki.openjdk.org/display/SKARA/Pull+Request+Commands#PullRequestCommands-/touch