Early access 0.8.1 version

New update with a couple of changes and fixes based on playtesting, feedback and bug reports.

Changes:

• Added an introduction hint to get started for first time players.
• The board cursor shadow now changes shape based on what you're placing next.
• Added a Give up button that is shown where there are just a few empty spaces left.
• Added a more pronounced animation to the last 10 sec tickdown animation for the time bar.
• Some improvement to shader pre-loading.
• Updated to new version of Godot engine.

Bug fixes:

• Fixed background gaps on edges of very wide screens.