Fix #23

[mirkobrombin]

Fix ERR_ABORTED for wrong filters.svg path.

I don't know if it's somehow intentional and if my fix breaks anything else (I do not think) but the demos on the site don't work because the filters.svg path is wrong as it looks for filters.svg in css/ but the main.css file is already in the css/ directory, so as a result the path became: css/css/filters.svg that is wrong.

Here the working demo: https://mirkobrombin.github.io/accecss/