Reset rake task uses Eson HTTP client instead of curl helper

* split compile method into two, one returns Hash, the other JSON string
Refactored reindex rake task

* input arguments are checked in the Eson client
Refactored create index rake task to use Eson client
Removed unused helper function now
Refactored alias rake task, more concise
Removed unnecessary function
Merge pull request #14 from Asquera/refactor/replace-curl-request-with-eson-http

Use Eson client instead of helper function in rake tasks
Merge remote-tracking branch 'origin/master' into refactoring/extract-rake-task-logic

Conflicts:
	lib/elasticsearch-rake-tasks.rake