Trimming teaser text

🚀 Features

• Teaser setting to limit its length #9 (@maxwroc)
• Exported built-in plugin interfaces #7 (@maxwroc)

🐛 Bug Fixes

• Fixed property-teaser text color #8 (@maxwroc)
• Added missing ctor interface #6 (@maxwroc)

🧰 Maintenance

• UI for changing plugin configuration on demo page #10 (@maxwroc)