add ability to version all projects as one

[philasmar]

Using the new setting UseSameVersionForAllProjects, users will now be able to force all the configured projects to use the same version. This version will be determined by the project with the currently highest version.
As an example, if you have 3 projects in your AutoVer config file with the following versions:

• Project 1 (1.20.0)
• Project 2 (1.25.0)
• Project 3 (1.30.0)

The version 1.30.0 will be used for future versioning. Depending on what increment type you are using, all projects will have the following version:

• Patch: 1.30.1
• Minor: 1.31.0
• Major: 2.0.0