Closes #3, closes #4 and README updates

## Fixes
 - #3 : Need to update license to Apache 2.0
 - #4 : Update default output path to **/allure-results 

## Changes 
 - README updates
  - how to `require` this gem in cucumber project
  - option to override the default output path 
  - remove unnecessary white spaces from code samples

cc: @smecsia