This makes them more reliable to parse. redo-log can parse each line,
format and print it, then recurse if necessary. This got a little ugly
because I wanted 'redo --raw-logs' to work, which we want to format the
output nicely, but not call redo-log.
(As a result, --raw-logs has a different meaning to redo and
redo-log, which is kinda dumb. I should fix that.)
As an added bonus, redo-log now handles indenting of recursive logs, so
if the build was a -> a/b -> a/b/c, and you look at the log for a/b, it
can still start at the top level indentation.
When we can't find a .do file, we walk all the way back to the root
directory. When that happens, the root directory is actually searched
twice. This is harmless (since a .do file doesn't exist there anyway)
but causes redo-whichdo to produce the wrong output.
Also, add a test, which I forgot to do when writing whichdo in the
first place.
To make the test work from the root directory, we need a way to
initialize redo without actually creating a .redo directory. Add a
init_no_state() function for that purpose, and split the necessary path
functions into their own module so we can avoid importing builder.py.
