Change alpha advert test to 100% of article audience
Different hosts for different variants
Setting the correct variable
Merge branch 'master' into alpha-advert-test

Conflicts:
	common/app/assets/javascripts/modules/experiments/ab.js
	common/app/assets/javascripts/modules/experiments/tests/alpha-
adverts.js
	common/app/conf/switches.scala
Merge branch 'master' into alpha-advert-test

Conflicts:
	common/app/assets/javascripts/modules/experiments/ab.js
	common/app/conf/switches.scala
ad dwell test
Changed test to measure advert dwell time
Increase audience to 10%
Merge pull request #2117 from guardian/alpha-advert-test

[DO NOT MERGE] Alpha advert test