Increase restclient execute timeout to 10 minutes
Increase restclient execute timeout to 10 minutes

The default timeout, if there's no console activity, is 60 seconds.
If a scraper has several dependencies to compile & install (buildpacks...),
it's not too difficult to hit this limit.

In these cases, the morph-cli run would die with something like the
following:

```
/var/lib/gems/2.1.0/gems/rest-client-1.8.0/lib/restclient/request.rb:427:in `rescue in transmit': Request Timeout (RestClient::RequestTimeout)
    from /var/lib/gems/2.1.0/gems/rest-client-1.8.0/lib/restclient/request.rb:350:in `transmit'
    from /var/lib/gems/2.1.0/gems/rest-client-1.8.0/lib/restclient/request.rb:176:in `execute'
    from /var/lib/gems/2.1.0/gems/rest-client-1.8.0/lib/restclient/request.rb:41:in `execute'
    from /var/lib/gems/2.1.0/gems/morph-cli-0.2.2/lib/morph-cli.rb:26:in `execute'
    from /var/lib/gems/2.1.0/gems/morph-cli-0.2.2/bin/morph:32:in `execute'
    from /var/lib/gems/2.1.0/gems/thor-0.19.1/lib/thor/command.rb:27:in `run'
    from /var/lib/gems/2.1.0/gems/thor-0.19.1/lib/thor/invocation.rb:126:in `invoke_command'
    from /var/lib/gems/2.1.0/gems/thor-0.19.1/lib/thor.rb:359:in `dispatch'
    from /var/lib/gems/2.1.0/gems/thor-0.19.1/lib/thor/base.rb:440:in `start'
    from /var/lib/gems/2.1.0/gems/morph-cli-0.2.2/bin/morph:63:in `<top (required)>'
    from /usr/local/bin/morph:23:in `load'
    from /usr/local/bin/morph:23:in `<main>'
```

This change sets the default timeout to 600 seconds, but will read a
config value (":timeout:") to override this as desired.

openaustralia/morph-cli