index.mdwn: update front page description, and add NANOG 60 links
remove dependency tree from the Architecture page

the dependency tree diagram is out of date now due to the removal of
libdnstap, addition of golang-framestream, etc., so delete it.
Tutorials/NANOG60.mdwn: new
index: change NANOG 60 code link to point to Tutorials/NANOG60
NANOG60: update
index: add quotes around the presentation titles
index: make the quotation marks consistent
dnstap.setup: add Tutorials page to bootmenu
Tutorials.mdwn: new
Source: update (fstrm, protobuf-c, golang-framestream, various tweaks)
Examples: "dnstap -s" -> "dnstap -u"
Tutorials/NANOG60: fill out
Tutorials/NANOG60: tweaks, fixes
index: use "Tutorial" rather than "Code" for the NANOG60 link
slides/dnstap_nanog60.pdf: new