readme instructions need updates

[cdnsteve]

Fixes for readme instructions:

In Setup step 2.

go get github.com/$github_user/clirescue.git
cd $GOPATH/src/github.com/clirescue

There were no instructions on GoBootCamp or in this readme to setup the environment variable, $github_user. This is confusing for someone getting started.

Stevens-MacBook-Pro:go$ echo $github_user

Stevens-MacBook-Pro:go$

Second command:

Stevens-MacBook-Pro:go xxx$ cd $GOPATH/src/github.com/clirescue
-bash: cd: /Users/xxx/go/src/github.com/clirescue: No such file or directory