ULTIMA6: Remove obsolete options from Nuvie options menu

[johnpevensie]

The Nuvie engine, used to run Ultima VI, is not well-integrated into ScummVM. For example, not only does the old options menu remain from Nuvie (accessible by pushing ESC), even though the original game did not have the options menu and other games implemented in ScummVM have game options in the ScummVM GMM, but there are a few options that are either no longer necessary or no longer work. Specifically, two options in the "Gameplay Options" should be removed:

"Startup game" - in the original Nuvie executable, this determined whether the player wanted to run Ultima VI, Savage Empire, or Martian Dreams on starting the application. This option is obsolete because ScummVM detects each of these games separately and allows the user to change between them with the GMM. I never tested this option, but I expect it to wreak havoc on accident.

"Use original cursors" - I think this was an option that was left over from early versions of Nuvie that did not yet support the Ultima VI cursors. All that disabling this option does now is remove the mouse cursor so that the player plays the game blind. The mouse still works even though the cursor does not show up.

In the long run, all of the options in the legacy Nuvie options menu should be integrated into the ScummVM menus. However, there are a few options that can be changed or removed soon:

In the "Video Options":

"Non-Square Pixels" - I don't know what this does and I don't think it affects much.
"Show Roofs" - this was a planned feature for Nuvie that was never finished. Right now, only a few roofs are implemented. The ScummVM developers must decide whether to finish roof mode or to remove it entirely, or at least remove the option and allow people to enable it from the configuration files.

In the "Audio Options":

"Enable Music" and "Enable SFX" - as the ScummVM menus allow you to mute and disable music and sound effects, these options may be obsolete.
"Music Volume" and "SFX Volume" - the same is true with the options to enable music and sound effects as with volume controls.

In the "Gameplay options":

"Skip intro" - I wonder if this was a debug option added by Nuvie. One can skip the intros already in Ultima VI now by pushing ESC or another key combo to get to the game itself. I don't know if this option is still necessary.

I have not documented other Nuvie options here. In the long term, the ScummVM menus should replace the legacy Nuvie options menu, although there are many options, some of which are currently only accessible by editing the configuration files (for example, adjusting the screen resolution of enhanced mode) - and ScummVM should both emulate original game behavior (in Original mode), and implement and allow the player to choose from Nuvie-provided enhancements (in Enhanced mode). Furthermore, these options behave differently between Ultima VI, Savage Empire, and Martian Dreams - the latter two are not yet supported, and some of them, even outside the "Cheats" menu, are cheats (e.g. choosing "None" for lighting mode).