TryFrom stable

TryFrom is now stable, so use that. Additionally re-export OrderedFloat since
it is used by the generated code. Relax dependencies to reduce downstream
conflicts.
diff --git a/lib/rs/src/protocol/binary.rs b/lib/rs/src/protocol/binary.rs
index 19aff3d..0920fc4 100644
--- a/lib/rs/src/protocol/binary.rs
+++ b/lib/rs/src/protocol/binary.rs
@@ -16,8 +16,7 @@
 // under the License.
 
 use byteorder::{BigEndian, ByteOrder, ReadBytesExt, WriteBytesExt};
-use std::convert::From;
-use try_from::TryFrom;
+use std::convert::{From, TryFrom};
 
 use super::{
     TFieldIdentifier, TInputProtocol, TInputProtocolFactory, TListIdentifier, TMapIdentifier,