Make many more utility classes/headers public. (#76)

Moving these headers from src to include enables other libraries to use the
functionality provided.

* tcpsockets
* atomic_static
* raw_istream
* timestamp
* SafeThread
* Base64
* LEB128
* ConcurrentQueue

The classes have been moved into the wpi namespace as they're generic.

include/tcpsockets/SocketError.h

@@ -0,0 +1,37 @@
+/*----------------------------------------------------------------------------*/
+/* 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_TCPSOCKETS_SOCKETERROR_H_
+#define WPIUTIL_TCPSOCKETS_SOCKETERROR_H_
+
+#include <string>
+
+#ifdef _WIN32
+#include <WinSock2.h>
+#else
+#include <errno.h>
+#endif
+
+namespace wpi {
+
+static inline int SocketErrno() {
+#ifdef _WIN32
+  return WSAGetLastError();
+#else
+  return errno;
+#endif
+}
+
+std::string SocketStrerror(int code);
+
+static inline std::string SocketStrerror() {
+  return SocketStrerror(SocketErrno());
+}
+
+}  // namespace wpi
+
+#endif  // WPIUTIL_TCPSOCKETS_SOCKETERROR_H_