Make upstart's noBackground check even more robust

Like f60e274, this commit fixes another JSON whitespace
issue with the upstart script's config file rewrite. It
also removes the added comment, in order to keep the config
file valid JSON.
Update README.md

Edits to ### 3. Connect your node to your friend's node to make it more clear to new users.
Can someone with better JSON confirm my "connectTo": section for multiple friends?
Set number of cpus to 1 if `os.cpus().length` is undefined.
Added comments to explain my reasoning in the code for future people.
Added a line for OS X users not to worry about.
Merge branch 'cpufix' of git://github.com/lukevers/cjdns
Merge branch 'patch-2' of git://github.com/lgierth/cjdns
Merge branch 'patch-1' of git://github.com/ntrlshrp/cjdns
Merge branch 'osx_tun' of git://github.com/lukevers/cjdns