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).
@krukow 

This is a breaking change I think.

Unless the user passes a value for `:uia_strategy`, `args` does not contain the key :uia_strategy and the value :preferences is never used.

On the run-loop side this means that the only script that is ever chosen is `run_loop_basic.js` [1] which I am pretty sure is not the expected behavior.

- [1] https://github.com/calabash/run_loop/blob/master/lib/run_loop/core.rb#L605