Grid Aware Templates

Improves shape detection for measured templates on gridded maps. The default algorithm in foundry checks if a grid center is within the preview shape and highlights according to that. This approach is a poor choice for games that rely heavily on grid spaces for measurements, leading to incorrectly highlighted areas.

This uses an alternative approach for highlighting spaces in circle and cone templates. For circles, all spaces within the radius of the template, as measured by grid spaces are highlighted. For cones, the circle area used, then spaces that aren't within the angle of the cone are removed. These alternate approaches give much nicer template highlighting, particularly for hexagonal grids.

To make these changes easier to use, templates will now snap to grid space increments for size and 15° increments for rotation during creation.