Move common utility classes to wpiutil library. (#79)

This is a breaking change to dependencies that use the static ntcore
library.  Unless the wpiutil library is also linked, linker errors will
result.  This does not affect the shared ntcore library.

wpiutil/include/support/leb128.h

@@ -0,0 +1,26 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) FIRST 2015. All Rights Reserved.                             */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#ifndef WPIUTIL_SUPPORT_LEB128_H_
+#define WPIUTIL_SUPPORT_LEB128_H_
+
+#include <cstddef>
+
+#include "llvm/SmallVector.h"
+
+namespace wpi {
+
+class raw_istream;
+
+std::size_t SizeUleb128(unsigned long val);
+std::size_t WriteUleb128(llvm::SmallVectorImpl<char>& dest, unsigned long val);
+std::size_t ReadUleb128(const char* addr, unsigned long* ret);
+bool ReadUleb128(raw_istream& is, unsigned long* ret);
+
+}  // namespace wpi
+
+#endif  // WPIUTIL_SUPPORT_LEB128_H_