Hardcopy of pybind11 instead of using git submodules (#552)

* removed pybind as submodule
* added hardcopy of pybind11 2.10.0
* rename pybind11 folder to avoid conflicts when changing branch

Co-authored-by: Dhanya Thattil <dhanya.thattil@psi.ch>

libs/pybind/include/pybind11/options.h

@@ -0,0 +1,76 @@
+/*
+    pybind11/options.h: global settings that are configurable at runtime.
+
+    Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>
+
+    All rights reserved. Use of this source code is governed by a
+    BSD-style license that can be found in the LICENSE file.
+*/
+
+#pragma once
+
+#include "detail/common.h"
+
+PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
+
+class options {
+public:
+    // Default RAII constructor, which leaves settings as they currently are.
+    options() : previous_state(global_state()) {}
+
+    // Class is non-copyable.
+    options(const options &) = delete;
+    options &operator=(const options &) = delete;
+
+    // Destructor, which restores settings that were in effect before.
+    ~options() { global_state() = previous_state; }
+
+    // Setter methods (affect the global state):
+
+    options &disable_user_defined_docstrings() & {
+        global_state().show_user_defined_docstrings = false;
+        return *this;
+    }
+
+    options &enable_user_defined_docstrings() & {
+        global_state().show_user_defined_docstrings = true;
+        return *this;
+    }
+
+    options &disable_function_signatures() & {
+        global_state().show_function_signatures = false;
+        return *this;
+    }
+
+    options &enable_function_signatures() & {
+        global_state().show_function_signatures = true;
+        return *this;
+    }
+
+    // Getter methods (return the global state):
+
+    static bool show_user_defined_docstrings() {
+        return global_state().show_user_defined_docstrings;
+    }
+
+    static bool show_function_signatures() { return global_state().show_function_signatures; }
+
+    // This type is not meant to be allocated on the heap.
+    void *operator new(size_t) = delete;
+
+private:
+    struct state {
+        bool show_user_defined_docstrings = true; //< Include user-supplied texts in docstrings.
+        bool show_function_signatures = true;     //< Include auto-generated function signatures
+                                                  //  in docstrings.
+    };
+
+    static state &global_state() {
+        static state instance;
+        return instance;
+    }
+
+    state previous_state;
+};
+
+PYBIND11_NAMESPACE_END(PYBIND11_NAMESPACE)