log output: initial move to DATADUMP

This moves most of the biggest log outputs from DEBUG and INFO to DATADUMP. Turns out, there weren't all that many.

Next I'm reevaluating the log level assigned to each output. Ideally I'm thinking the default log level should be INFO (20) and should give the user a good picture of what their node is doing on the network without being too much or too many to read in realtime.
Yes but only on the grounds that we're changing the quotes based on the presence or absence of escape sequences.

Whether we enclose human-readable strings in single quotes or double quotes is fairly immaterial to me but I do think we should consistently do one or the other. Maybe there's a stronger Pythonic objection to escape sequences than I'm yet familiar with, but inconsistent style seems worse to me than single-level escapes.

The most widely used [style](http://stackoverflow.com/questions/56011/single-quotes-vs-double-quotes-in-python#56190) I've encountered encloses the whole string in double quotes, the nickname in double quotes, and the type in single quotes.

This style I linked is what I propose we use if we don't yet have one. If we do have or choose a different one then that's just as well and I'm happy to use it instead. This one appears simply to stem from a C-like background so there's probably not much logic behind it except that it seems very popular.