Merged language fixes and link updates from @annonn.

* Closes #80.
* Squashed and merged.
* Within `true`, now using "let us" instead of "let's" so it looks better when actually debugging the script. If this is of concern (very very minor issue for me, since only a message for debugging purposes, only for devs), feel free to rephrase it so it doesn't need "let us" or apostrophes.
* Changed text to:

    '"DisableNetwork 0" was already uncommented in /etc/tor/torrc. Tor should be activated.

    Note: whonixsetup activates Tor by uncommenting "DisableNetwork 0" in /etc/tor/torrc. There is no need to run it multiple times, and it probably not the cause of network problems. You can manually check if "DisableNetwork 0" is uncommented in /etc/tor/torrc.