New mode for multiBarChart called "stacked normalized" with 0-100% domain

This pull request mplements a new mode for multiBarChart called "stacked normalized". It displays bars in stacked format but normalized values from 0-100%.

## Modified files:
* models/multiBarChart.js
* models/multiBar.js
* test/multiBarChartTest.html (added new chart 8)

## Examples:
* examples/multiBarChartNorm.html

## Notes/Limitations:
For backward compatibility reasons to old multiCharts the new feature is only enabled if "allowNormalized" is passed to the chart during construction.
The current version technically works (meaning it does not crash) with negative values but the output is mainly crap. In order to keep modifications as small as possible the chart function in multiBar.js now internally works on a deep copy of the original data. Normalization will then modify the actual values of that copied data to to 0.0-1.0 domain. All other logic and access to variables did not need modification.
The chart.state() function in multiBarChart.js will now always dispatch a changeState event if a new state is passed in.