Support Calabash Lite mode which uses pure UIAutomation

Calabash Lite is a mode of operation where we can execute automated tests without needing the Calabash server. Only a smaller subset of operations are supported.

To use, call `relaunch` or `start_test_server_in_background` with data similar to: 

```
{calabash_lite: true, app:'com.example.app', device_target:'device'}
```

The option `uia_strategy` is also supported and passed on to run_loop (see https://github.com/calabash/run_loop/pull/18).
```
uia_strategy = args[:uia_strategy] || :preferences
```

`uia_strategy` is an _unused_ variable.

`args` does not contain the key `:uia_strategy`.

I _think_ this is what you want:

```
unless args[:uia_strategy]
  args[:uia_strategy] = :preferences
end
```