Add Assimp library in thirdparty

From https://github.com/assimp/assimp repo at d2b45377e4b09a1f43be95e45553afcc06b03f4b

thirdparty/assimp/code/StdOStreamLogStream.h

@@ -0,0 +1,101 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2019, assimp team
+
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+copyright notice, this list of conditions and the
+following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the
+following disclaimer in the documentation and/or other
+materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+contributors may be used to endorse or promote products
+derived from this software without specific prior
+written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file  StdOStreamLogStream.h
+*  @brief Implementation of StdOStreamLogStream
+*/
+
+#ifndef AI_STROSTREAMLOGSTREAM_H_INC
+#define AI_STROSTREAMLOGSTREAM_H_INC
+
+#include <assimp/LogStream.hpp>
+#include <ostream>
+
+namespace Assimp    {
+
+// ---------------------------------------------------------------------------
+/** @class  StdOStreamLogStream
+ *  @brief  Logs into a std::ostream
+ */
+class StdOStreamLogStream : public LogStream {
+public:
+    /** @brief  Construction from an existing std::ostream
+     *  @param _ostream Output stream to be used
+    */
+    explicit StdOStreamLogStream(std::ostream& _ostream);
+
+    /** @brief  Destructor  */
+    ~StdOStreamLogStream();
+
+    /** @brief  Writer  */
+    void write(const char* message);
+
+private:
+    std::ostream& mOstream;
+};
+
+// ---------------------------------------------------------------------------
+//  Default constructor
+inline StdOStreamLogStream::StdOStreamLogStream(std::ostream& _ostream)
+: mOstream   (_ostream){
+    // empty
+}
+
+// ---------------------------------------------------------------------------
+//  Default constructor
+inline StdOStreamLogStream::~StdOStreamLogStream() {
+    // empty
+}
+
+// ---------------------------------------------------------------------------
+//  Write method
+inline void StdOStreamLogStream::write(const char* message) {
+    mOstream << message;
+    mOstream.flush();
+}
+
+// ---------------------------------------------------------------------------
+
+}   // Namespace Assimp
+
+#endif // guard