Add an Update Check

[Corionis]

Add a mechanism to check for updates.

Because the free version of Advanced Installer does not provide auto-update capability one step in the right direction would be to:

1. Keep a text file in the GitHub repository containing the version and build numbers.
2. The values can be written to the file with the build batch files.
3. In CSM use an HTTP request to download and read that file - is that possible?
4. Inform the user of the update with appropriate information and a clickable link.