Formalize the cumulative hierarchy V (most of §10.5 of the book)
Change the style of the comments
Move the dependent composition to Overture.v
Rename "bitot" as "bitotal"
Move is_mono_isinj to minus1Trunc.v
Add the Irreflexive & Asymmetric type classes to Overture.v
Make use of [transparent assert] in the proof of bisimulation.
Make use of curly braces, adjust indentation.
Split the proof of bisimulation again (this is much faster).
Forgot to update a file
Make V_comt_setext vacuous, change comment style
Merge pull request #440 from jledent/master

Formalize the cumulative hierarchy V (most of §10.5 of the book)