Rewrite REPL using pure Lua
Add support for remote connection in interactive console

Use require('console').connect(host, port) in interactive mode to
connect console to remote host:

```
./src/tarantool: version 1.6.2-257-g8d89b64
tarantool> box.cfg{primary_port = 3301}
---
...
tarantool> require('console').connect('127.0.0.1', 3301) <!-- connect
---
...
127.0.0.1:3301> remote_command
---
- result
...
127.0.0.1:3301> [CTRL+D] <!-- disconnect from remote
tarantool> local_command
---
- result
...

```

This patch uses CALL(dostring) to execute commands on remote server.
Merge remote-tracking branch 'origin/gh-338-remote-console'

Conflicts:
	src/lua/yaml.cc