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/lib.rs b/lib/rs/src/lib.rs
index ca5c7d6..a36ec99 100644
--- a/lib/rs/src/lib.rs
+++ b/lib/rs/src/lib.rs
@@ -49,9 +49,9 @@
 #![doc(test(attr(allow(unused_variables), deny(warnings))))]
 
 extern crate byteorder;
+extern crate ordered_float;
 extern crate integer_encoding;
 extern crate threadpool;
-extern crate try_from;
 
 #[macro_use]
 extern crate log;
@@ -85,3 +85,6 @@
 /// As is convention this is a typedef of `std::result::Result`
 /// with `E` defined as the `thrift::Error` type.
 pub type Result<T> = std::result::Result<T, self::Error>;
+
+// Re-export ordered-float, since it is used by the generator
+pub use ordered_float::OrderedFloat as OrderedFloat;
\ No newline at end of file