run simplecov locally when running tests
fix html_view: display check results

because of commit 19b7fcedca "add checker name in the checker results"

the check results contains a hash and the html view had not been adapted
to that on that commit.
test Gemfile contains gems-status

test gems-status with gems-status
add a gems-status version in Gemfile.lock that does not exist

for testing purposes
simplify: only one source and textview instead of html

This commit simplifies the gems-status.
From now on, only one source since that is what we are actually using.
The lockfile is only one gemfile.lock. That simplifies the software.
Output in text format instead of html. That simplifies the view a lot,
and since there is the gems-status-web project, we don't need the html.
clean an unused variable
fix tests
review the sources and the checkers

Experience has demonstrate that we only use one of the sources, the one
that gets the info from a Gemfile.lock and that the checkers needed to
be reviewed, rewrited, some remove and some new added.