first try on new next/prev
many bug fixes and accuracy improvements for iteration
Talmud and Talmud Commentary iteration
Merge branch 'master' into next_prev_ref
Merge branch 'master' into next_prev_ref

Conflicts:
	reader/views.py
ToC - link to first available text vs head of section.
fix to talmud index formula?
minor fix
Merge branch 'master' into next_prev_ref
small comments add