Package from the future protection

### Overall scope ###

When as user have an older version of Dynamo, it's possible that they might attempt to download a package created with a newer version of Dynamo than their current one.  This pull request adds functionality to show a simple MessageBox when a user attempts to do this.  They are still allowed to move forward, but have the opportunity to cancel a package download (include all of its dependencies).  

### Messagebox!? ###

I think that we could add additional improvements to the UI for this work with a nicely styled MessageBox, but it doesn't seem like a high priority at the moment.  I'm open to suggestion, though.  

### Other changes ###

This pull request also changes Dynamo to use the domain name dynamopackages.com and no longer shows an uninstall dialog when a package is being installed and the user has already approved the uninstall.  

### Unit tests ###

Fairly scant, this just introduces a unit test demonstrating the version checking logic.  This method only tests the major, minor, and build numbers (major.minor.build) so users with the different revision numbers (e.g. bleeding edge users) can still share packages amongst each other without seeing the dialog.