Skip CF deployment if CF_API is not defined
Skip CF deployment if CF_API is not defined

Builds from pull requests will skip CF deployment to our test account.
Fixes #199.

jsdelfino/d-abacus,jsdelfino/d-abacus,pombredanne/cf-abacus,jsdelfino/cf-abacus-experiment,KRuelY/cf-abacus,18F/cf-abacus,nmaslarski/cf-abacus,cloudfoundry-incubator/cf-abacus,BetaFood/cf-abacus-dev,jsdelfino/x-abacus,18F/cf-abacus,nmaslarski/cf-abacus,jsdelfino/x-abacus,danparsons/cf-abacus,nmaslarski/cf-abacus,KRuelY/cf-abacus,danparsons/cf-abacus,pombredanne/cf-abacus,jsdelfino/cf-abacus-experiment,KRuelY/cf-abacus,danparsons/cf-abacus,rajkiranrbala/cf-abacus,cloudfoundry-incubator/cf-abacus,jsdelfino/cf-abacus-experiment,jsdelfino/x-abacus,rajkiranrbala/cf-abacus,rajkiranrbala/cf-abacus,pombredanne/cf-abacus,rajkiranrbala/cf-abacus,jsdelfino/d-abacus,nmaslarski/cf-abacus,BetaFood/cf-abacus-dev,jsdelfino/d-abacus,18F/cf-abacus,cloudfoundry-incubator/cf-abacus,BetaFood/cf-abacus-dev,jsdelfino/x-abacus,pombredanne/cf-abacus,KRuelY/cf-abacus