[winecfg 1] Implement saveConfigValue(), style changes, code cleanup, UI alignment

[Mike Hearn]

ChangeLog:
- Correct return code of loadConfig()
- Make the registry key used a constant
- Change registry key used to WineHQ\Wine
- Made code slightly more consistant with itself
- Some style changes, expanding out variable names, whitespace, removing
unnecessary variable initializers and hungarian notation etc
- Replace dialog box with a FIXME in WinMain() to warn of incompleteness
- Implement saveConfigValue()
- Hook up support for save/load of WinVer