Revert "move log subscrition to a log controller"

This was causing the log to not refresh sometimes when switching from
one repo to another, I'm reverting for now, we will have to have another
look.

This reverts commit 2e8b74160cf55aa5644997511c9a8fc3f767dd0c.

Conflicts:
	assets/scripts/app/controllers/build.coffee
	assets/scripts/app/models/build.coffee
	assets/scripts/app/templates/builds/show.hbs
	assets/scripts/app/views/log.coffee
	assets/scripts/vendor/log.js