Refactor folder (#10475)

Move many third-party components' source codes from the src folder to a new folder called deps_src. The goal is to make the code structure clearer and easier to navigate.

deps_src/libigl/igl/file_exists.cpp

@@ -0,0 +1,16 @@
+// This file is part of libigl, a simple c++ geometry processing library.
+// 
+// Copyright (C) 2013 Alec Jacobson <alecjacobson@gmail.com>
+// 
+// This Source Code Form is subject to the terms of the Mozilla Public License 
+// v. 2.0. If a copy of the MPL was not distributed with this file, You can 
+// obtain one at http://mozilla.org/MPL/2.0/.
+#include "file_exists.h"
+
+#include <sys/stat.h>
+
+IGL_INLINE bool igl::file_exists(const std::string filename)
+{
+  struct stat status;
+  return (stat(filename.c_str(),&status)==0);
+}