Setup TravisCI to report cov stats to coveralls.io.

Also add a coveralls.io test coverage badge to the README.

.travis.yml

@@ -3,3 +3,8 @@ go:
   - release
   - tip
 install: go get -d -t -v ./...
+script: go test -v -covermode=count -coverprofile=profile.cov
+after_success:
+  - go get -v github.com/mattn/goveralls
+  - export PATH=$PATH:$HOME/gopath/bin
+  - goveralls -coverprofile=profile.cov -service=travis-ci

README.md

@@ -2,7 +2,9 @@ btcwire
 =======
 
 [![Build Status](https://travis-ci.org/conformal/btcwire.png?branch=master)]
-(https://travis-ci.org/conformal/btcwire)
+(https://travis-ci.org/conformal/btcwire) [![Coverage Status]
+(https://coveralls.io/repos/conformal/btcwire/badge.png?branch=master)]
+(https://coveralls.io/r/conformal/btcwire?branch=master)
 
 Package btcwire implements the bitcoin wire protocol.  A comprehensive suite of
 tests with 100% test coverage is provided to ensure proper functionality.  See