plugin skeleton for deis

fixed test cases
Merge pull request #735 from PierreKircher/master

deploy plugin for "DEIS PAAS"
fix --deploy and --publish flags to `drone build`
parse build file with params injection
Merge pull request #745 from shawnzhu/deploy

`drone build --deploy` doesn't work as expected
Merge pull request #746 from shawnzhu/inject-params

parse build file with params injection