feat(client): add a new Client struct with super powers

- Includes ergonomic traits like IntoUrl and IntoBody, allowing easy
usage.
- Client can have a RedirectPolicy.
- Client can have a SslVerifier.

Updated benchmarks for client. (Disabled rust-http client bench since it
hangs.)

src/lib.rs

@@ -138,6 +138,7 @@ extern crate mucell;
 pub use std::io::net::ip::{SocketAddr, IpAddr, Ipv4Addr, Ipv6Addr, Port};
 pub use mimewrapper::mime;
 pub use url::Url;
+pub use client::Client;
 pub use method::Method::{Get, Head, Post, Delete};
 pub use status::StatusCode::{Ok, BadRequest, NotFound};
 pub use server::Server;
@@ -181,6 +182,10 @@ macro_rules! inspect(
     })
 )
 
+#[cfg(test)]
+#[macro_escape]
+mod mock;
+
 pub mod client;
 pub mod method;
 pub mod header;
@@ -191,7 +196,6 @@ pub mod status;
 pub mod uri;
 pub mod version;
 
-#[cfg(test)] mod mock;
 
 mod mimewrapper {
     /// Re-exporting the mime crate, for convenience.
@@ -208,7 +212,7 @@ pub enum HttpError {
     /// An invalid `Method`, such as `GE,T`.
     HttpMethodError,
     /// An invalid `RequestUri`, such as `exam ple.domain`.
-    HttpUriError,
+    HttpUriError(url::ParseError),
     /// An invalid `HttpVersion`, such as `HTP/1.1`
     HttpVersionError,
     /// An invalid `Header`.
@@ -223,7 +227,7 @@ impl Error for HttpError {
     fn description(&self) -> &str {
         match *self {
             HttpMethodError => "Invalid Method specified",
-            HttpUriError => "Invalid Request URI specified",
+            HttpUriError(_) => "Invalid Request URI specified",
             HttpVersionError => "Invalid HTTP version specified",
             HttpHeaderError => "Invalid Header provided",
             HttpStatusError => "Invalid Status provided",
@@ -234,6 +238,7 @@ impl Error for HttpError {
     fn cause(&self) -> Option<&Error> {
         match *self {
             HttpIoError(ref error) => Some(error as &Error),
+            HttpUriError(ref error) => Some(error as &Error),
             _ => None,
         }
     }
@@ -245,6 +250,12 @@ impl FromError<IoError> for HttpError {
     }
 }
 
+impl FromError<url::ParseError> for HttpError {
+    fn from_error(err: url::ParseError) -> HttpError {
+        HttpUriError(err)
+    }
+}
+
 //FIXME: when Opt-in Built-in Types becomes a thing, we can force these structs
 //to be Send. For now, this has the compiler do a static check.
 fn _assert_send<T: Send>() {