Add a step resource, logs, and logchunks
fix tests to use identifiers
factor out common code for navigating the builder/build/step/log hierarchy
Use URI-like strings to specify paths
use 'i:xx' for identifiers and 'n:xxx' for numbers
omit the /number/ to identify steps by number
update README.md
move logchunks to their own resource type and module
update documentation for pathPatterns
update README.md
Merge branch '9/statusdb' into nine
pyflakes