Add option to customize default values for emulator settings

[lmills87]

For example, I would like to add certain windowed and/or fullscreen resolutions, or certain output modes. I'm DOSBox ECE 4035 which features a patch called "pixel-perfect", and it adds the following output modes:

surfacepp
surfacenp
surfacenb
openglnb

I would like to add these as options to the output drop-down box when creating a template. And of course it would be helpful to change other default values as well, as they may change or be updated with future releases of DOSBox.

[theMK2k]

I heard from DOSBox ECE the first time. I'm in contact with the maintainer in order to officially support it and its patches.

I'll look into the user-defined enhancement of DOSBox options.

[theMK2k]

DOSBox ECE is now supported with all its patches in v1.1.0.

I'll keep this issue open because we want to support user-defined values, which is currently not implemented.