Console errors reporting NaN

[andrewgoz]

I've found in some cases window.getComputedStyle() is returning empty strings for styles.paddingLeft/Right. The following line:

charts/src/js/utils/dom.js

Line 85 in 8f69be0

parseFloat(styles.paddingLeft) + parseFloat(styles.paddingRight);

should probably be changed to something like:

parseFloat(styles.paddingLeft || '0') + parseFloat(styles.paddingRight || '0')

[yunsuklee]

Hey! Should get fixed with the following PR #418. Hope its usefull.

I also added some element type checking.