Updates to README

[VitalyMCT]

I think the following areas are in need of an update in the README:

1. Describe current installation process. It appears to be to run download-Install-MIS-Azure-Visio-Package.ps1 or Install-MIS-Azure-Visio-Package.ps1 instead of using the previous manual file-by-file copying process.

2. Update the package version numbers, or remove them altogether.

3. Update references to Visio versions

4. Update references to package stencils

5. How to upgrade from one package version to another (simply rerun the installer PS, clean up first, etc.)

This is a partial list. There could be other updates required as well. Thanks.

[sandroasp]

points 2 and 4 fixed... I'm working on the others