Revise Import Tasks

To support phrase collections:

• add new action of list import tasks of a project with status filtering
• update show import task to support phrase collections

Rename Items to Phrase Collections

Merge pull request #5 from onesky/victor/rename-items

Victor/rename items

Add items and item attachments

New resource

• Items
• Item Attachments

API with basic features

• Locales
• Project Types
• Project Groups
• Projects
• Files
• Translations
• Import Tasks
• Screenshots