Check for Updates Functionality

[Robert Leach]

Create a preference setting to check for updates on startup (and a list of ignored updates - see below).

A lot of forethought should be put into the URL that is used, because it should work in all future versions. If a new version is available, there should be a notification to the user with 4 options:

1. Cancel - to simply dismiss the window (it will pop up on next launch)
2. Ignore this update - so they don't get notified on subsequent runs (unless another even newer version becomes available)
3. Ignore all - this should change the preference setting for "check for updates"
4. Download - Opens the download webpage

Also - It's notable that if the user blows away the preferences file, these settings will get blasted too.

[Robert Leach]

Removing milestone: General interface (automated comment)