Rename daisy-export-path to manifest-path

and use it also for archiving
Split encoding and archiving into two separate namespaces
Add functions to get the encoded and the iso path

of a production
Add a new state :encoded

for productions which have been encoded and are now ready for archiving.
Move the db schema from CamelCase to underscores

This is better as explained in http://stackoverflow.com/a/14319048

For simplicity sake I just used the same underscore names in the
keywords. This is apparently not very idiomatic. Oh well, maybe we will
change this later.
Add a function to present keywords as labels in the UI
Remove dead code
Add a function to convert a string to a state