Reimplement public interface for stability

More information to come later about this, but this is a result of the
work week discussions we've had about stabilizing procedural macros

Author: alexcrichton

.travis.yml

@@ -3,7 +3,7 @@ sudo: false
 
 matrix:
   include:
-    - rust: 1.15.0
+    - rust: 1.23.0
     - rust: stable
     - rust: beta
     - rust: nightly

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "proc-macro2"
-version = "0.2.3" # remember to update html_root_url
+version = "0.3.0" # remember to update html_root_url
 authors = ["Alex Crichton <[email protected]>"]
 license = "MIT/Apache-2.0"
 readme = "README.md"