Add into_map function

This is useful when i.e. you need to return a HashMap from a function,
and you're hiding the use of a Counter as an implementation detail.

Closes #6.

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "counter"
-version = "0.4.0"
+version = "0.4.1"
 authors = ["Peter Goodspeed-Niklaus <peter.r.goodspeedniklaus@gmail.com>"]
 description = "Simple package to count generic iterables"
 repository = "https://github.com/coriolinus/counter-rs"

src/lib.rs

@@ -71,6 +71,11 @@ where
             }
         }
     }
+
+    /// Consumes this counter and returns a HashMap mapping the items to the counts.
+    pub fn into_map(self) -> HashMap<T, N> {
+        self.map
+    }
 }
 
 impl<T, N> Counter<T, N>