[PATCH] winecfg: don't trash app names

[Rafał Mużyło]

Currently, if app name isn't representable in CP_ACP, it gets trashed
during creation. There's no reason for it - the name is originally
retrived as widechar string. This isn't the cleanest way, but still one
that works.

gothas: enumerate_values is no longer usable for other maens, yet this
was its only use; reg_key_exists becomes unused; {g,s}et_app_reg_key
copy a lot of existing code, instead of reusing

minor note: winecfg could use a better check for KEY_WOW64_32KEY case -
in my experience, it's quite often that key created by winecfg should
actually under Wow6432Node, otherwise it has no effect.