Add jline2 to SBT library dependencies.

JLine is a Java library for handling console input. It is similar in
functionality to BSD editline and GNU readline:
https://github.com/jline/jline2
Don't show password in plain text.

Use jline's ConsoleReader.readLine(Character) which reads the next line with
the specified character mask.
Add tab completion of action names to GameClientConsole.

Use jline's Completer to support tab completion of action names.
Make GameClientConsole take the base URL as an argument.

If no base URL is given, http://localhost:9000 is used by default.
Get the list of action names by parsing routes file.

Don't hardcode action names in GameClientConsole. Instead, parse routes file
and get the list of action names for auto completion.
Introduce BeyondJavaScriptEngine.

BeyondJavaScriptEngine is responsible for execution of JavaScript.
Make GamePluginWorker take an instance of BeyondJavaScriptEngine.
Extract initialization of BeyondGlobal as init method.
Make it possible to pass a BeyondGlobal instance to BeyondJavaScriptEngine.
Add BeyondShellGlobal.

BeyondShellGlobal is a subclass of BeyondGlobal which provide additional
features for shell console. Currently, only quit is added.
Add JavaScriptShellConsole.

JavaScriptShellConsole is an interactive JavaScript shell.
Make it possible to set an ErrorReporter to BeyondContextFactory.
Use TotalErrorReporter in JavaScriptShellConsole.

TotalErrorReporter intercepts exceptions and prints them to stderr.
Add tab auto-completion to JavaScriptShellConsole.