Show "Alias" for packages in "platformio show" command

platformio/commands/show.py

@@ -23,7 +23,10 @@ def cli(platform):
 
     pm = PackageManager(platform)
     for name, data in pm.get_installed(platform).items():
+        pkgalias = p.get_pkg_alias(name)
         echo("----------")
         echo("Package: %s" % style(name, fg="yellow"))
+        if pkgalias:
+            echo("Alias: %s" % pkgalias)
         echo("Location: %s" % join(pm.get_platform_dir(), data['path']))
         echo("Version: %d" % int(data['version']))

platformio/platforms/base.py

@@ -40,6 +40,9 @@ class BasePlatform(object):
         else:
             raise NotImplementedError()
 
+    def get_pkg_alias(self, pkgname):
+        return self.PACKAGES[pkgname].get("alias", None)
+
     def pkg_aliases_to_names(self, aliases):
         names = []
         for alias in aliases: