add some utf8 converting methods

add new methods:
- bool int_to_stream(int c, pt::Stream & stream);
- template<typename OutputFunction>
  bool utf8_to_output_function(const Stream & stream, OutputFunction output_function, int mode = 1);
- template<typename StreamIteratorType, typename OutputFunction>
  bool utf8_to_output_function(StreamIteratorType & iterator_in, const StreamIteratorType & iterator_end, OutputFunction output_function, int mode = 1);
- template<typename StreamType, typename OutputFunction>
  bool wide_to_output_function(StreamType & buffer, OutputFunction output_function, int mode = 1);

make some methods public:
- size_t wide_to_int(const wchar_t * wide_string, size_t string_len, int & z, bool & correct)
- size_t wide_to_int(const wchar_t * wide_string, int & z, bool & correct)

rename and make some methods public:
- template<typename OutputFunction>
  utf8_to_wide_generic(const char * utf8, size_t utf8_len, OutputFunction convert_function, int mode) -> utf8_to_output_function(...)

while here:
- fix: correctly convert characters in Log::put_multiline_generic()

src/space/space.cpp

@@ -34,8 +34,10 @@
 
 #include <wchar.h>
 #include "space.h"
-#include "utf8/utf8.h"
 #include "convert/convert.h"
+#include "textstream/textstream.h"
+#include "utf8/utf8.h"
+
 
 
 namespace pt