fix -Wdeprecated-copy warnings in string algorithms

Author: apolukhin

Diff for: include/boost/algorithm/string/detail/find_iterator.hpp

@@ -40,18 +40,26 @@ namespace boost {
             // Protected construction/destruction
 
                 // Default constructor
-                find_iterator_base() {}
+                BOOST_DEFAULTED_FUNCTION(find_iterator_base(), {})
+
                 // Copy construction
-                find_iterator_base( const find_iterator_base& Other ) :
+                BOOST_DEFAULTED_FUNCTION(find_iterator_base( const find_iterator_base& Other ), :
                     m_Finder(Other.m_Finder) {}
+                )
+
+                // Assignment
+                BOOST_DEFAULTED_FUNCTION(find_iterator_base& operator=( const find_iterator_base& Other ), {
+                    m_Finder = Other.m_Finder;
+                    return *this;
+                })
 
                 // Constructor
                 template<typename FinderT>
                 find_iterator_base( FinderT Finder, int ) :
                     m_Finder(Finder) {}
 
                 // Destructor
-                ~find_iterator_base() {}
+                BOOST_DEFAULTED_FUNCTION(~find_iterator_base(), {})
 
                 // Find operation
                 match_type do_find( 

Diff for: include/boost/algorithm/string/find_iterator.hpp

@@ -74,7 +74,7 @@ namespace boost {
 
                 \post eof()==true
             */
-            find_iterator() {}
+            BOOST_DEFAULTED_FUNCTION(find_iterator(), {})
 
             //! Copy constructor
             /*!
@@ -85,6 +85,18 @@ namespace boost {
                 m_Match(Other.m_Match),
                 m_End(Other.m_End) {}
 
+            //! Copy assignment
+            /*!
+                Assigns a copy of the find_iterator
+            */
+            BOOST_DEFAULTED_FUNCTION(find_iterator& operator=( const find_iterator& Other ), {
+                if (this == &Other) return *this;
+                this->base_type::operator=(Other);
+                m_Match = Other.m_Match;
+                m_End = Other.m_End;
+                return *this;
+            })
+
             //! Constructor
             /*!
                 Construct new find_iterator for a given finder
@@ -248,6 +260,20 @@ namespace boost {
                 m_bEof(Other.m_bEof)
             {}
 
+            //! Assignment operator
+            /*!
+                Assigns a copy of the split_iterator
+            */
+            BOOST_DEFAULTED_FUNCTION(split_iterator& operator=( const split_iterator& Other ), {
+                if (this == &Other) return *this;
+                this->base_type::operator=(Other);
+                m_Match = Other.m_Match;
+                m_Next = Other.m_Next;
+                m_End = Other.m_End;
+                m_bEof = Other.m_bEof;
+                return *this;
+            })
+
             //! Constructor
             /*!
                 Construct new split_iterator for a given finder