Make portable by load & saving settings from INI instead of registry

[atifaziz]

Addresses #19.

There is still some clean-up and tweaking needed but it's functionally there so that changes so far can be reviewed.

Note that I had to bring in LINQBridge to be able to use LINQ while still targeting .NET 2.0. If we target .NET 3.5 (which should be a safe baseline for Windows 7 but perhaps not Vista) then I can remove that dependency. In any event, it's not an external or binary dependency; it's completely embedded so AeroShot remains a single executable.

[toehead2001]

Go ahead target .NET 3.5, and remove the LINQBridge dependency.

I would prefer that all the code in the project was using the same license. The MIT license is of course GPL compatible, so if you really want to use that code, that's fine.