Silence warnings from itensor

[asartori86]

@jurajHasik,
I silenced the warnings from itensor, yet there are many from our source code. I'll silence some of them in a future PR, but the rest should be tackeld by you

In reference to #3

[jurajHasik]

Just a little change, since the name was changed for p-ipeps to pi-peps, something like
for n in grep -rnw . 'p-ipeps'; do sed -i 's/p-ipeps/pi-peps/g' $n
to switch to reflect new name ?