Upgrade RVM to 1.18.8
Upgrade RVM to 1.18.8

* Fixes Rubygems SSL issue #221

webcoyote/pivotal_workstation,webcoyote/pivotal_workstation,Yesware/sprout,wendorf/sprout-osx-apps,1000Bulbs/pivotal_workstation,wendorf/sprout-osx-apps,1000Bulbs/sprout,Yesware/sprout,pivotal-sprout/sprout-osx-apps,1000Bulbs/sprout,1000Bulbs/pivotal_workstation,pivotal-sprout/sprout-osx-apps,pivotal-sprout/sprout-osx-apps,Yesware/sprout,wendorf/sprout-osx-apps,webcoyote/pivotal_workstation