zero a lot of uninitialized member vars

[0x08088405]

Legal Stuff:

By submitting this pull request, I confirm that...

• My changes may be used in a future commercial release of VVVVVV (for
  example, a 2.3 update on Steam for Windows/macOS/Linux)
• I will be credited in a CONTRIBUTORS file for all of said releases, but
  will NOT be compensated for these changes

Changes:

I'm not sure why you need debug + RTC but a good chance is that it's related to uninitialized values which are zeroed in debug but not release (had this exact mystery headache a while ago). This just sets a bunch of otherwise uninitialized member vars to 0, also getting rid of one compiler warning per variable initialized. Neat.

Also fixes a spelling error (forground) in the graphics class's buffers.

[flibitijibibo]

Odd, for some reason none of these ever showed up in a Valgrind test (and still don't, to my knowledge). But yes, I will very happily take initialized memory fixes as they're found. Go ahead and add your name to desktop_version/CONTRIBUTORS.txt and I'll merge this in.

[0x08088405]

Sure, hope that's good (just put a domain there that points to my GitHub since I intend on changing my username).
There's probably more uninitialized memory errors, there were some with the labclass type classes but they have an associated function for constructing (instead of a constructor) which is why it raised warnings so those are probably fine. I'll look for more weird ones later.

[flibitijibibo]

Thanks! No rush on this, but I'm definitely glad someone is interested in fixing the bizarre VS issues...

[flibitijibibo]

Thought I had this on file from a previous patch, but it turns out I don't... can you fill this out for me real quick?

## Legal Stuff:

By submitting this pull request, I confirm that...

- [ ] My changes may be used in a future commercial release of VVVVVV (for
  example, a 2.3 update on Steam for Windows/macOS/Linux)
- [ ] I will be credited in a `CONTRIBUTORS` file for all of said releases, but
  will NOT be compensated for these changes

[0x08088405]

I wish GitHub would notify me, good thing I checked my PR for no particular reason.

Legal Stuff:

By submitting this pull request, I confirm that...

• My changes may be used in a future commercial release of VVVVVV (for
  example, a 2.3 update on Steam for Windows/macOS/Linux)
• I will be credited in a CONTRIBUTORS file for all of said releases, but
  will NOT be compensated for these changes

[flibitijibibo]

Awesome, thanks! (Also GitHub pls)