Update README_Install_Mac.md
Update README_Install_Mac.md

- changed syntax to markdown
- minor fixes
monotek/zammad,monotek/zammad,monotek/zammad,zammad/zammad,zammad/zammad,zammad/zammad,monotek/zammad,zammad/zammad,zammad/zammad,monotek/zammad,monotek/zammad,zammad/zammad