improve README
add Fotolife#index comments
add Fotolife#_toJson
add Fotolife#_toXml test
refactoring
refactoring Fotolife#constructor
bump the version number to 0.2.4
improve README
add q dependency
use Promise in Fotolife#_toJson
use Promise in Fotolife#_toXml
use Promise in Fotolife#_request
improve comments
fix validation for Promise
add validation
remove gulp
add response validation
add some examples
improve README
bump the version number to 0.3.0