Bug fixes

• Fix the exception "Unknown downloader type: npm-signature" (#321, #324)

Improvements

• Improve performance by removing dev dependencies (#269, 3ec92aa5f07ed7398c37b54e0442048abc5306bd)
• Update doc (b8f99831d4cc9fdb7ebf53204dfcbf443586d94f)

Requirements:

Composer version: ^1.6.0. Installation: must be do in global mode.