Several reader issues fixed

- Fix boot2docker url
- move HomeBrew instructions to a separate section
- fix docker client 5-liner to work (its still ugly)
- fix and update program output

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@fosiki.com> (github: SvenDowideit)
Merge pull request #5592 from SvenDowideit/docs-simplify-osx-install

Several OSX install reader issues fixed