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.

include/support/raw_socket_istream.h

@@ -0,0 +1,31 @@
+/*----------------------------------------------------------------------------*/
+/* 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_RAW_SOCKET_ISTREAM_H_
+#define WPIUTIL_SUPPORT_RAW_SOCKET_ISTREAM_H_
+
+#include "support/raw_istream.h"
+#include "tcpsockets/NetworkStream.h"
+
+namespace wpi {
+
+class raw_socket_istream : public raw_istream {
+ public:
+  raw_socket_istream(NetworkStream& stream, int timeout = 0)
+      : m_stream(stream), m_timeout(timeout) {}
+  virtual ~raw_socket_istream() = default;
+  virtual bool read(void* data, std::size_t len);
+  virtual void close();
+
+ private:
+  NetworkStream& m_stream;
+  int m_timeout;
+};
+
+}  // namespace wpi
+
+#endif  // WPIUTIL_SUPPORT_RAW_SOCKET_ISTREAM_H_