At post-install, ask the user to turn on autocompletion

Introduce the "autocomplete" command to allow user to turn it on when they need it.

Author: teobugslayer

lib/common

@@ -1,14 +1,3 @@
 "use strict";
 var child_process = require("child_process");
-var command = process.argv[0] + ' bin/nativescript.js dev-post-install';
-child_process.exec(command, function(error, stdout, stderr) {
-	if (stdout !== null && stdout.toString() !== "") {
-		console.log('stdout: ' + stdout);
-	}
-	if (stderr !== null && stderr.toString() !== "") {
-		console.log('stderr: ' + stderr);
-	}
-	if (error !== null) {
-		console.log('exec error: ' + error);
-	}
-});
+child_process.spawn(process.argv[0], ["bin/nativescript.js", "dev-post-install"], {stdio: "inherit"});

postinstall.js

@@ -30,6 +30,7 @@ General commands:
     device run                      Runs the selected application on a connected device.
     device list-applications        Lists the installed applications on all connected devices.  
     feature-usage-tracking          Configures anonymous feature usage tracking.
+    autocomplete                    Turn on command line autocompletion for bash and zsh
 
 General options:
     --help, -h, /?      Prints help about the selected command.
@@ -682,4 +683,13 @@ All data gathered is used strictly for improving the product and will never be u
              for improving the product and will never be used to identify or contact you.
     disable - Disables anonymous usage statistics tracking.
 
---[/]--
+--[/]--
+
+--[autocomplete]--
+
+Turns on command line autocompletion for bash and zsh.
+
+Usage:
+    $ tns autocomplete
+
+--[/]--