Use std::string_view and fmtlib across all libraries (#3402)

- Twine, StringRef, Format, and NativeFormatting have been removed
- Logging now uses fmtlib style formatting
- Nearly all uses of wpi::outs/errs have been replaced with fmt::print() or
std::puts()/std::fputs() (for unformatted strings).
- A wpi/fmt/raw_ostream.h header has been added to enable
fmt::print() with wpi::raw_ostream

hal/src/main/native/sim/HAL.cpp

@@ -4,10 +4,10 @@
 
 #include "hal/HAL.h"
 
+#include <cstdio>
 #include <vector>
 
 #include <wpi/mutex.h>
-#include <wpi/raw_ostream.h>
 #include <wpi/spinlock.h>
 
 #ifdef _WIN32
@@ -351,7 +351,11 @@ HAL_Bool HAL_Initialize(int32_t timeout, int32_t mode) {
   }
 #endif  // _WIN32
 
-  wpi::outs().SetUnbuffered();
+#ifndef _WIN32
+  setlinebuf(stdin);
+  setlinebuf(stdout);
+#endif
+
   if (HAL_LoadExtensions() < 0) {
     return false;
   }