Drop dependency on try_from.

This bumps the minimum supported stable Rust version to 1.34.

The TryFrom and TryInto traits are still reexported to not break the
API, but these reexports are deprecated and will be removed in a future
release.

src/muc/muc.rs

@@ -98,7 +98,7 @@ mod tests {
     use crate::util::error::Error;
     use minidom::Element;
     use std::str::FromStr;
-    use try_from::TryFrom;
+    use std::convert::TryFrom;
 
     #[test]
     fn test_muc_simple() {

src/muc/user.rs

@@ -9,7 +9,7 @@ use crate::util::error::Error;
 use crate::ns;
 use jid::Jid;
 use minidom::Element;
-use try_from::TryFrom;
+use std::convert::TryFrom;
 
 generate_attribute_enum!(
 /// Lists all of the possible status codes used in MUC presences.
@@ -89,7 +89,7 @@ pub enum Actor {
 }
 
 impl TryFrom<Element> for Actor {
-    type Err = Error;
+    type Error = Error;
 
     fn try_from(elem: Element) -> Result<Actor, Error> {
         check_self!(elem, "actor", MUC_USER);