Make it possible to set graph style per series basis.

I.e. now we can have line bar and area on the same graph for instance.
Also some minor bugs have been fixed and minor enhancemnts has been done:
 * Fix 'y' axis formatting. Now we always use toFixed(2)
 * Fix 'logScaling' checkbox. We should use jelly 'checkbox' component
   instead of plain 'html' checkbox.
 * Add points display for line graph style.