touch: restore wintouchemu, fall back to it when native touch hooks fail (#834)

## Link to GitHub Issue or related Pull Request, if one exists
Fixes #833

## Description of change
Last couple PRs - such as #820 #827 #828 - made the native touch hook &
touch injection using `InjectTouchInput` the default path, since it
performs much more reliably with both real touch screens and mouse (or
any other synthetic source).

However, user has reported that WINE lacks `InjectTouchInput` which
means this won't work.

As a fix, revive the old wintouchemu code. Native touch is still the
default, but under following circumstances:

1. if `-touchemuforce` is set, or
2. if any of the required Windows touch APIs are unavailable

then we fail over from native touch to wintouchemu code. 

For Linux, condition #2 would be hit during init, and gracefully switch
over.

Caveat: the poke code for IIDX and Nost will continue to require native
touch, I do not want to maintain two paths for this. This means that
iidx poke will stop working on Linux, unfortunately.

## Testing
Tested on Windows with `-touchemuforce` set. This is mostly reverting
Linux code path back to where we were last release, so this should just
work with wine.

src/spice2x/games/iidx/iidx.h

@@ -28,6 +28,8 @@ namespace games::iidx {
     extern bool TDJ_MODE;
     extern bool FORCE_720P;
     extern bool DISABLE_ESPEC_IO;
+    extern bool NATIVE_TOUCH;
+    extern bool ENABLE_POKE;
     extern std::optional<std::string> SOUND_OUTPUT_DEVICE;
     extern std::optional<std::string> ASIO_DRIVER;
     extern uint8_t DIGITAL_TT_SENS;
@@ -52,6 +54,7 @@ namespace games::iidx {
 
         virtual void attach() override;
         virtual void pre_attach() override;
+        virtual void post_attach() override;
         virtual void detach() override;
 
     private: