Propagate more error information

Signed-off-by: Casey Dahlin <casey.dahlin@gmail.com>
Tests for error propagation

Signed-off-by: Casey Dahlin <casey.dahlin@gmail.com>
Don't split the queue by Levenshtein distance

This was useful for an earlier architecture but doesn't buy us anything now.

Signed-off-by: Casey Dahlin <casey.dahlin@gmail.com>
Another tweak to compareRecovery

The last softening of Levenshtein distance's sway on the algorithm was too
much. This makes it much firmer. The result should be more thorough in every
way. The only remaining question is if performance will suffer on larger
workloads.

Signed-off-by: Casey Dahlin <casey.dahlin@gmail.com>
Add string attribute to EPState

Occasionally useful for debugging, and does no harm being present.

Signed-off-by: Casey Dahlin <casey.dahlin@gmail.com>