Really? I'd say "on" is pretty clearly a preposition— here meaning "onward". Since "on" isn't often used in that sense except in the case of compounds like "go on", "move on", "drive on" etc. it might make more sense to say that "go on" is a phrasal verb and a single lexical item. (Note that we could replace "go on" in its entirely with a more semantically shallow "leave" without affecting the rest of the sentence.)
"To" is tricky because it seems that we can replace it with a conjunction and maintain the meaning of the sentence— "I go on and start Woven" does mean nearly the same thing. However, you need to look at the ellipsis (linguisticspeak for omission): "I go on and [I] start Woven" makes sense. "I go on to [I] start Woven" obviously doesn't work. So we've actually changed the structure of the sentence, meaning our replacement is no good.
It makes more sense to see the "to" as attached to the infinitive "start", with the form working as an adverb of reason: "Why do you go on? To start Woven." The actual implied conjunction here is probably "in order". (If you're feeling clever, the infinitive also assumes the subject of the main clause, thus the ellipsis: "I go on [in order] [for me] to start Woven.")
So by my analysis, both of those words are actually part of verb forms. Uncapitalizing either seems to separate them from their verb phrase, causing the confusion we've seen. However I'd recommend, especially in this informal context, just using normal sentence capitalization, which everyone will have no trouble parsing— and which is how the title is capitalized on the blog itself!
I'm not a big fan of that headline style - it tends to look a bit cheesy in my opinion. I think it's mor of a US newspaper thing - the NY Times do it, but guardian.co.uk doesn't. To be fair, neither does the washingtonpost.com
