Add --help and --version options

To get --help you need to use -- --help because of
ceylon/ceylon-common#38.

source/ceylon/formatter/options/formattingOptions.ceylon

@@ -52,6 +52,60 @@ Map<String,Anything(VariableOptions)> presets = HashMap {
 };
 
 shared [FormattingOptions, String[]] commandLineOptions(String[] arguments = process.arguments) {
+    // first of all, the special cases --help and --version, which both cause exiting
+    if (arguments.contains("--help")) {
+        print(
+            "ceylon.formatter – a Ceylon module / program to format Ceylon source code.
+             
+             USAGE
+             
+                 ceylon run ceylon.formatter source
+             
+             or, if you’re worried about it breaking your source code (which shouldn’t happen –
+             if anything bad happens, error recovery kicks in and the original file is destroyed)
+             or you just want to test it out:
+             
+                 ceylon run ceylon.formatter source --to source-formatted
+             
+             You can also format multiple folders at the same time:
+             
+                 ceylon run ceylon.formatter source --and test-source --to formatted
+             
+             which will recreate the ‘source’ and ‘test-source’ folders inside the new ‘formatted’ folder.
+             
+             OPTIONS
+             
+             --help
+                 Print this help message.
+             
+             --version
+                 Print version information. The first line is always just the module name and version
+                 in the format that ‘ceylon run’ understands (“ceylon.formatter/x.y.z”), which might be
+                 useful for scripts.
+             
+             --${option name}=${option value}
+                 Set a formatting option. See the documentation of the FormattingOptions class for a list of
+                 options. The most useful ones are:
+                 
+                 --maxLineLength
+                     The maximum line length, or “unlimited”.
+                 
+                 --indentMode
+                     The indentation mode. Syntax: “x spaces” or “y-wide tabs” or “mix x-wide tabs, y spaces”.
+                 
+                 --lineBreak
+                     “lf”, “crlf”, or “os” for the operating system’s native line breaks."
+        );
+        process.exit(0);
+    } else if (arguments.contains("--version")) {
+        print(
+            "`` `module ceylon.formatter`.name ``/`` `module ceylon.formatter`.version ``
+             Copyright 2014 Lucas Werkmeister
+             Licensed under the Apache License, Version 2.0."
+        );
+        process.exit(0);
+    }
+
     variable FormattingOptions baseOptions = configOptions();
 
     String[] splitArguments = concatenate(*arguments.map((String s) {