lots of nice stuff

Yes, terrible committing etiquette. Oh well, I think I can keep
track of what I did when, well enough.

a few things that I notice at this point:
1. some tables in the metadata view have text overflow
2. still need to be able to create codices with no ismi data
3. possibly the list of manuscripts should be automatically drawn
from the images folder
4. witnesses should be able to store their final page since there
seem to be codices where some page ranges have no identified witness;
also when validating we'll have to make sure there is no overlap
between entered values.