Enhancements of line-chart

- Adding settings to linechart
  - all parts are configurable now, so it can be used e.g. as smaller
    version for sparklines
  - auto_size and auto_resize are now configurable
  - added option for static y axis, drafted how it will be done
    for static x axis

- Added inline documentation of each function and method

Implements blueprint horizon-reusable-charts

Change-Id: I4352bc7946d3141bacc1c964de61e55a42521da6
Merge "Enhancements of line-chart"