bumping Plek to 1.0.0

Run  to test
adding govuk_setenv to jenkins
tweaking for govuk_setenv envvar set up
Merge remote branch 'origin/master' into bump-plek

Conflicts:
	Gemfile
	Gemfile.lock
Use latest Plek for it's niceness
Merge pull request #42 from alphagov/bump-plek

Bump plek