copied util.inherits method to local file

When using the util library, a lot of extra unneeded code is added to the build. Just by copying the code from the inherits method to a local file saves about 7kb in filesize (when minified!)

````
with util/inherits --> cat build/fluxxor.min.js | wc -c: 29566 chars
with inherits.js -->   cat build/fluxxor.min.js | wc -c: 22399 chars
````