CSS colors no longer work with spaces in parentheses

[ArcanoxDragon]

Description/Steps to reproduce

After my most recent paper.js upgrade, a lot of the colors in my project have turned to Black. I discovered that this is because my color string constants are in the format rgba( red, green, blue, alpha ) instead of rgba(red, green, blue, alpha) (notice the space after the opening and before the closing parentheses). In the previous version, this worked fine, but now it is parsing to pure black. The CSS standard supports spaces in the parentheses like this, so paper should ideally support them as well.

Link to reproduction test-case

Reproduction in paper sketch

All versions prior to 0.11.8 work fine, whereas 0.11.8 parses the second shape as black.

Expected result

Both squares in the example should have the same color, but in the latest version, the latter shape is black.

[ArcanoxDragon]

This line is likely to be the offending line:

da3a362#diff-523d1801bcd0534360a437e5481626eaR74

After that commit, the parser splits on [,\s]+ instead of just , but does not filter out empty components. The first space now acts as a split character and the first component is an empty string.

[sapics]

Thanks @briman0094 for reporting bug and analyzing detail!
I create a PR #1633 to fix this issue.