add trailing slash

- avoids redirect, pointed out by "http://validator.w3.org/checklink"
fixed broken link to pulseaudio and jack

- this link seems to have been broken for a long time, see 'archive.org'
- redirected to the page about Pulseaudio and Jack
ad trailing slashes and remove broken anchor

- trailing slash to avoid redirect
- remove anchor since w3c validator states it is broken on opensrc.org,
  which seems true