Allow full config

[ilyavf]

Simply bit-c3 to accept a config object which will be passed to c3 to generate chart.

Issues: #19, #23

Config object:

let config = {
  axis: {
    x: {
      type: 'category',
      tick: {
        rotate: -45,
        multiline: false
      },
      height: 130
    }
  }
};
let axisXData = new DefineList(['x','cat 1','cat 2','cat 3'])

Template:

<bit-c3 {config}="config">
	<bit-c3-data type="{type}">
		{{#each dataColumns}}
			<bit-c3-data-column value="{.}" {axis-x}="axisXData" />
		{{/each}}
	</bit-c3-data>
</bit-c3>

Will generate barchart with x category labels rotated by -45: