Mp Dev Tools version 0.1.0

• Some minor fixes.
• Upload select (drop-down) with example.
• Example for multiple select (drop-down).
• Additional parameter (options) for selects (drop-downs).
• Retrieve selected ids of selected categories, articles, content types, and upload files.
• Unified string identifier, replaced cat_<id> with idcat:<id>, and art_<id> with idcatart:<id>.