Implement bonus fruit

[nucleartide]

User Story

test.mov

• Fruit. At 70 dots, a bonus fruit (pineapple mesh) appears directly below the pen.
• Scoring. Fruit is worth 100 to 5000 points depending on the level.
• Second fruit. At 170 dots, if the first fruit has been collected another fruit will appear.
• Temporariness. Fruit disappears after 10 seconds.
• UI. The symbols for the last 3 levels are shown on the bottom right.

Playable build

https://drive.google.com/file/d/1mJIC82mSikxQo0utOKyIT2U2zJAHUEtE/view?usp=sharing

Dev checklist

• First draft. Implement a working first pass at the feature. If it helps, try thinking about data (model), presentation (view), and logic (controller).
• Design by contract. Write pre-condition, post-condition, and invariant assertions to catch bugs before playtesting.
• Unit tests. If needed, write unit tests to tease out edge cases.
• First playtest. Thoroughly playtest until you are confident that the feature (and existing features) work. This also exercises the code paths with contracts.
• Final draft. Perform a general review of Files changed and revise anything that needs to be cleaned up.
• Run unit tests.
• Final playtest. After the changes above, playtest through the game one last time to ensure that everything works.
• Fill out the pull request template. Self-explanatory.
• Remember the GIFs. Include a recording of what's going on!
• Merge. Merge into master.

Release checklist

• Build. Cut a new build in Unreal. If the game doesn't build, fix until it does.
• Tag. Once built, tag the latest commit on master with the latest version string.
• Upload. Upload build to Google Drive.
• Link. Add link to this pull request.
• Priorities. Prioritize items on work board.
• Next task. Tee up a pull request for the next feature.