Update PowerShell commands (#176)

* Update PowerShell commands

* Update README.md

Adding in more commands

preview/MsixCore/README.md

@@ -49,17 +49,26 @@ Sample packages can be found at msix-packaging/preview/MsixCore/tests; these can
 certutil -addstore root APPX_TEST_ROOT.cer
 ```
 
-Installation - Using command prompt or PowerShell, navigate to the directory that contains the executables and run the following command to install notepadplus.msix.
-
+Installation - Using command prompt or PowerShell, navigate to the directory that contains the executables and run the following command to install notepadplus.msix. The -quietUX parameter can also be added at the end of the command so that users don't see the installer UI.
 ```
 msixmgr.exe -AddPackage C:\SomeDirectory\notepadplus.msix
 ```
-
-Uninstallation - 
-
+Querying for Installed MSIX Packages - 
+```
+msixmgr.exe -FindAllPackages
+```
+Querying for a specific MSIX Package -
+```
+msixmgr.exe -FindPackage notepadplus_0.0.0.1_x64__8wekyb3d8bbwe
+```
+Uninstallation - The -quietUX parameter can also be used here.
 ```
 msixmgr.exe -RemovePackage notepadplus_0.0.0.1_x64__8wekyb3d8bbwe
 ```
+Unpacking -
+```
+msixmgr.exe -Unpack notepadplus.msix
+```
 
 ## Build Status
 [![Build status](https://microsoft.visualstudio.com/xPlatAppx/_apis/build/status/CIGitHub-for-MsixCoreInstaller)](https://github.com/Microsoft/msix-packaging/releases/tag/MsixCoreInstaller-preview)