Revisions to generic.xml

Here is a first run at revising generic.xml to better handle prose and verse text.  Hopefully enough specificity has been added to the CSS rules.
As a general rule I think `<div>` and `<p>` should be `display: block` regardless of type and `.tei-seg` and `<span>` `display:inline`.  Defaulting to `display: block` helps put well defined and predetermined constraints around content whereas `display: inline` would leave you at the mercy of the undetermined content itself.