feat(lib): replace types with those from http crate

BREAKING CHANGE: `Method`, `Request`, `Response`, `StatusCode`,
  `Version`, and `Uri` have been replaced with types from the `http`
  crate. The `hyper::header` module is gone for now.

  Removed `Client::get`, since it needed to construct a `Request<B>`
  with an empty body. Just use `Client::request` instead.

  Removed `compat` cargo feature, and `compat` related API.

src/common/mod.rs

@@ -1,6 +1,2 @@
-pub use self::str::ByteStr;
-
-mod str;
-
 #[derive(Debug)]
 pub enum Never {}

src/common/str.rs

@@ -1,57 +0,0 @@
-use std::ops::Deref;
-use std::str;
-
-use bytes::Bytes;
-
-#[derive(Debug, Clone, PartialEq, Eq, Hash)]
-pub struct ByteStr(Bytes);
-
-impl ByteStr {
-    pub unsafe fn from_utf8_unchecked(slice: Bytes) -> ByteStr {
-        ByteStr(slice)
-    }
-
-    pub fn from_static(s: &'static str) -> ByteStr {
-        ByteStr(Bytes::from_static(s.as_bytes()))
-    }
-
-    pub fn slice(&self, from: usize, to: usize) -> ByteStr {
-        assert!(self.as_str().is_char_boundary(from));
-        assert!(self.as_str().is_char_boundary(to));
-        ByteStr(self.0.slice(from, to))
-    }
-
-    pub fn slice_to(&self, idx: usize) -> ByteStr {
-        assert!(self.as_str().is_char_boundary(idx));
-        ByteStr(self.0.slice_to(idx))
-    }
-
-    pub fn as_str(&self) -> &str {
-        unsafe { str::from_utf8_unchecked(self.0.as_ref()) }
-    }
-
-    pub fn insert(&mut self, idx: usize, ch: char) {
-        let mut s = self.as_str().to_owned();
-        s.insert(idx, ch);
-        let bytes = Bytes::from(s);
-        self.0 = bytes;
-    }
-
-    #[cfg(feature = "compat")]
-    pub fn into_bytes(self) -> Bytes {
-        self.0
-    }
-}
-
-impl Deref for ByteStr {
-    type Target = str;
-    fn deref(&self) -> &str {
-        self.as_str()
-    }
-}
-
-impl<'a> From<&'a str> for ByteStr {
-    fn from(s: &'a str) -> ByteStr {
-        ByteStr(Bytes::from(s))
-    }
-}