VideoConfig: Change convergence setting to percentage value.

[CrossVR]

This makes more sense for people maintaining the convergence values in the game settings.

[CrossVR]

@SMarioMan Could you test the build of this PR?

[SMarioMan]

@Armada651 I tested it out in Donkey Kong Country Returns. I needed to move the stereo convergence slider over exactly 30 ticks (130% in the global settings file) to make it work. Otherwise Donkey Kong wasn't in the convergence plane.
I'm starting to have second thoughts about what I said before. I am completely confident that the values I entered had used a global default with the slider all the way to the left and the game-specific minimum added to it. If there's a default of 30 added in somewhere outside of those ini files, I didn't account for them. Were you were referring to the slider in the global config panel? If it's just a matter of adding 30 to each setting, that's fine by me, but I thought that I knew what I was talking about.
Also, its really hard to get the slider exactly at 100% because it doesn't have any snapping. I'm sure you'll address things like that later though.

[CrossVR]

Yeah I still have to figure out how I want to do snapping at 100%. It's very strange that you have to add 30 ticks to the global slider, how did you initially find the convergence values? Using the global slider or the ticker in the game properties?

[SMarioMan]

@Armada651 When I first found the values, I used a combination of game properties and global slider to find the value. Then I summed them together (grabbing the specific values from the ini files) and put that value in the game properties section and turned the global slider all the way down. That worked prefectly for me.

[CrossVR]

@SMarioMan The default value in the game properties was 20, correct?

[SMarioMan]

@Armada651 I honestly have no clue off the top of my head. The difficulty of setting it to such a specific value was why I set the game inis to assume a global value of 0 though.

[CrossVR]

@SMarioMan Try adding a value of 20 to all convergence values and setting the convergence slider back to 100% (I'd just edit your Dolphin.ini for now).

[CrossVR]

Ready for review, I dropped the upgrade code from this PR. Instead I suggest we cherry-pick at least this change to the stable so we don't get too many people using the previous method of setting the convergence value.

[CrossVR]

For reference, this is what the new slider looks like: https://www.dropbox.com/s/ubj74862tf7syuv/Schermafdruk%202015-09-19%2016.38.01.png?dl=0

[SMarioMan]

@Armada651 Changing the StereoConvergence value in Dolphin-x64\Sys\GameSettings\SF8.ini seems to do nothing for me in Donkey Kong Country Returns with the latest version of your PR. Still requires me to increment the slider by 30 ticks (70 ticks from the right).
Also, it would be convenient if the slider wouldn't always snap when you get close to it, for those that want to manually set a value between 90-110%. A modifier key like Ctrl or something would be nice.

[degasus]

sounds fine to me, but needs a rebase.

[CrossVR]

@degasus This PR is ready for review.

[SMarioMan]

This PR seems to have completely broken the convergence values I've found. Neither StereoConvergenceMinimum nor StereoConvergence values seem to change anything for me when I adjust them in the default inis.

[CrossVR]

@SMarioMan You are right, I think a line was dropped in my rebase. I'll file a new PR to fix this.

EDIT: It was not lost in the rebase, it was just moved to the Video_Enhancements section. I'll submit a PR to move those to the stereoscopy section.