v0.6.2

Changes

• Partial renderer rework to favor understanding of which entities are selected/highlighted;
• improved things angle indicator by drawing it in code instead of using an image;
• added MANUAL.md, for those who prefer to read the manual in a separate file instead of using the built-in one;
• improved app-manual consistency.

Fixes

• Fixed height tooltip of the highlighted entity drawn slightly off-center;
• fixed sprites not being rendered when picking the brushes to spawn after a clip;
• fixed extrusion/intrusion not being initiated right after Alt clicking on a previously non-selected side;
• fixed vertexes/nodes selection when the area described by the mouse drag includes all of the surface of the owning entity.