v1.3.0

1.3.0 cleans up area helpers.

Changes:

• area and perimeter helpers now return numbers by default
• helpers return strings only when a unit suffix is provided
• added triangleArea while keeping traingleArea as a compatibility alias
• fixed triangle area calculation to use 0.5 * base * height

Validation:

• npm test
• npm pack --dry-run
• npm publish via v1.3.0 tag