Updates to fix PHP 8.5.1 compatibility issues.

Fix draggable legend not appearing in FireFox.

Merge pull request #83 from jasper-eljakim/master

Ignore errors/warnings/notices for the iconv test

Merge pull request #80 from pdscopes/master

Added option to specify nonce when fetching javascript

Fix compatibility with PHP 7.2.

Updates for version 3.20.

Constrain lines to grid area.

Added support for curved best-fit lines using best_fit="curve".

Fixed font_size and line_spacing support in text shapes.

Fixed font_size and line_spacing support in individual guidelines.

Use actual font size for default line spacing.

Added support for px, in, cm, mm, pt and pc CSS units in font sizes.

Now throws exception when non-numeric font size used.