(GH-1054) Ensure Admin Runs w/Admin Context

Ensure that Chocolatey runs with administrative context every time when
an administrative user is running Chocolatey.

src/chocolatey.console/app.manifest

@@ -16,7 +16,7 @@
             If you want to utilize File and Registry Virtualization for backward 
             compatibility then delete the requestedExecutionLevel node.
         -->
-        <requestedExecutionLevel level="asInvoker" uiAccess="false" />
+        <requestedExecutionLevel level="highestAvailable" uiAccess="false" />
       </requestedPrivileges>
     </security>
   </trustInfo>