Rely on doc.rs for documentation hosting (except master)

Closes #20

.travis.yml

@@ -29,4 +29,4 @@ after_success: |
   kcov --coveralls-id=$TRAVIS_JOB_ID --verify --include-pattern=/src --exclude-pattern=/.cargo,/usr/lib target/kcov target/debug/prettytable-*
   rm -Rf master.tar.gz kcov-master
   git clone https://gist.github.com/deaf3815d2eecce72279.git ./publish_doc &&
-  sh ./publish_doc/publish_doc.sh prettytable
+  sh ./publish_doc/publish_doc.sh prettytable yes

Cargo.toml

@@ -5,7 +5,7 @@ version = "0.6.7"
 description = "A library for printing pretty formatted tables in terminal"
 homepage = "https://github.com/phsym/prettytable-rs"
 repository = "https://github.com/phsym/prettytable-rs"
-documentation = "http://phsym.github.io/prettytable-rs"
+documentation = "https://docs.rs/crate/prettytable-rs/"
 readme = "README.md"
 authors = [ "Pierre-Henri Symoneaux" ]
 keywords = ["tab", "table", "format", "pretty", "print"]

README.md

@@ -3,12 +3,12 @@
 [![Build status](https://ci.appveyor.com/api/projects/status/wdh9klb35fed6ik9?svg=true)](https://ci.appveyor.com/project/phsym/tabprint)
 [![Coverage Status](https://coveralls.io/repos/phsym/prettytable-rs/badge.svg?branch=master)](https://coveralls.io/github/phsym/prettytable-rs?branch=master)
 [![Crates.io](https://img.shields.io/crates/v/prettytable-rs.svg)](https://crates.io/crates/prettytable-rs)
+[![Doc.rs](https://docs.rs/prettytable-rs/badge.svg)](https://docs.rs/crate/prettytable-rs/)
+[![Doc.rs](https://img.shields.io/badge/docs-master-blue.svg)](http://phsym.github.io/prettytable-rs/master)
 
 # prettytable-rs
 
-A formatted and aligned table printer written in rust.
-
-[Documentation](http://phsym.github.io/prettytable-rs)
+A formatted and aligned table printer library for [Rust](https://www.rust-lang.org).
 
 *Copyright © 2017 Pierre-Henri Symoneaux*