Boost Framerates up 30FPS

So far, all versions of openBVE have been targeting the .NET Framework 2. I made this choice because I wanted to maximize compatibility with Mono, and because I don't need any functionality from more recent versions of the Framework. Therefore, I didn't want users to undergo a potentially large download unless there were a compelling reason.

But, newer versions of the .NET Framework come with more efficient compilers that can produce faster code. Simply updating your .NET Framework version to 4 is not enough though, because Microsoft made the choice to let different .NET Framework versions exist side by side. This means that openBVE has to specifically target the .NET Framework 4 before you can get any benefit. I tested both Framework versions and found that switching to .NET 4 indeed gives better performance in openBVE on some routes.

I invite you to test performance with the most recent openBVE version and to compare the .NET 2 and .NET 4 builds. If you do, please make sure that vertical synchronization is turned off and that you use the same settings.

These are my results for some (relatively high) settings:

Solyomvar
v1.4.0.9 (.NET 2): 90 fps
v1.4.0.9 (.NET 4): 213 fps

Hammersmith - Edgware Road
v1.2.14: 47 fps
v1.4.0.9 (.NET 2): 53 fps
v1.4.0.9 (.NET 4): 68 fps

Northern Line
v1.2.14: 34 fps
v1.4.0.9 (.NET 2): 39 fps
v1.4.0.9 (.NET 4): 67 fps

All releases in the 1.4 series will be offered for both .NET 2 and .NET 4 so nobody has to upgrade unless they want to. All releases in the 1.5 series and upward will only be offered for .NET 4