fix crash when coming list is empty
add filter Format in default formatters
[senscritique] continue browser2 adaptation
Fix conversion warning
Fix conversion warning
Hide wrong pyflakes/flake8 error
Remove unused/obsolete parsers

lxmlsoup is currently used by one module.
Also check arguments with is_here()

Otherwise, something like that would never work:
page.stay_or_go(id=1)
page.stay_or_go(id=2)  # would stay on URL for id=1

To avoid breaking simple usage of is_here(), if no arguments are
provided, then there are no checks.

That means:
page.stay_or_go(id=1)
page.stay_or_go()  # nothing happens