Myst: Fullscreen flyby videos should loop and be clickable

[mgiuca]

Version: 2.1.0git
Games: Myst Masterpiece Edition (GOG version, June 2018)
OS: Windows 10
Type of bug: Departure from original game behaviour

Steps to reproduce:

1. Open any of the Age books in Myst island (e.g., spoiler warning, go to pillars and press Leaf, Beetle and Snake, then open door in boat beside dock).
2. Click the small animated video on the book.
3. Observe the full-screen flyby video.

Expected behaviour:
The full-screen flyby video loops forever. The mouse cursor is visible. Clicking anywhere on the screen ends the video and links to the Age.

(This is the behaviour in the original Windows Myst Masterpiece edition.)

Actual behaviour:
The full-screen flyby video plays exactly once, then auto-links to the Age. The mouse cursor is hidden and clicking does not skip the video. User can press Esc (not documented) to skip the video.

Problems with the new behaviour:

• The video is intended to loop. Automatically linking after it plays once feels abrupt.
• The Esc shortcut is undocumented, so players may not realise they can skip this video.

[bgK]

In bc983b82:

MOHAWK: MYST: Loop the flyby movies and allow skipping using left click

Fixes #10599.