Add support for --host

- Fixes missing `var index;`.
- Removes search for `-d` which is never there since TiCLI translates this to `--project-dir`.
- Adds support for `--host` or `-o` to select the host for express.

The last one I need to select `localhost` for testing offline scenarios in sim/emulator.

@dbankier tested both the addition and the change, apart and in combination.
@yomybaby please test again ;)