Solve compiler warning about using deprecated item.

PutBackN::new() is replaced by put_back_n.

src/printf/memo.rs

@@ -7,7 +7,7 @@
 
 use std::iter::Peekable;
 use std::slice::Iter;
-use itertools::PutBackN;
+use itertools::put_back_n;
 use cli;
 use tokenize::token::{Token, Tokenizer};
 use tokenize::unescaped_text::UnescapedText;
@@ -26,7 +26,7 @@ impl Memo {
     pub fn new(pf_string: &String, pf_args_it: &mut Peekable<Iter<String>>) -> Memo {
         let mut pm = Memo { tokens: Vec::new() };
         let mut tmp_token: Option<Box<Token>>;
-        let mut it = PutBackN::new(pf_string.chars());
+        let mut it = put_back_n(pf_string.chars());
         let mut has_sub = false;
         loop {
             tmp_token = UnescapedText::from_it(&mut it, pf_args_it);

src/printf/tokenize/num_format/formatter.rs

@@ -1,7 +1,8 @@
 //! Primitives used by num_format and sub_modules.
 //! never dealt with above (e.g. Sub Tokenizer never uses these)
+
 use std::str::Chars;
-use itertools::PutBackN;
+use itertools::{PutBackN, put_back_n};
 use cli;
 use super::format_field::FormatField;
 
@@ -57,7 +58,7 @@ pub trait Formatter {
     fn primitive_to_str(&self, prim: &FormatPrimitive, field: FormatField) -> String;
 }
 pub fn get_it_at(offset: usize, str_in: &str) -> PutBackN<Chars> {
-    PutBackN::new(str_in[offset..].chars())
+    put_back_n(str_in[offset..].chars())
 }
 
 // TODO: put this somewhere better

src/printf/tokenize/sub.rs

@@ -8,7 +8,7 @@ use std::iter::Peekable;
 use std::str::Chars;
 use std::process::exit;
 use cli;
-use itertools::PutBackN;
+use itertools::{PutBackN, put_back_n};
 use super::token;
 use super::unescaped_text::UnescapedText;
 use super::num_format::format_field::{FormatField, FieldType};
@@ -371,7 +371,7 @@ impl token::Token for Sub {
                                 })
                             }
                             'b' => {
-                                let mut a_it = PutBackN::new(arg_string.chars());
+                                let mut a_it = put_back_n(arg_string.chars());
                                 UnescapedText::from_it_core(&mut a_it, true);
                                 None
                             }