Pass tool list into Chart initialization

[birdsarah]

Is this a BUG REPORT or FEATURE REQUEST?:

Uncomment only one, leave it on its own line:

type: bug

type: feature

I'd like to be able to pass the tools argument into Chart e.g. p = chartify.Chart(x_axis_type='categorical', blank_labels=True, tools='wheel_zoom, save')

Anything that's accepted for bokeh's figure would be acceptable and would get passed in here: https://github.com/spotify/chartify/blob/master/chartify/_core/chart.py#L175

With default as tools='save' so this would be a non-breaking API change.

(I'm a bokeh dev, so I'm very familiar with writing bokeh code and so naturally want to do tweak things. I understand that in a wrapper library like this the whole point is to provide an abstraction. I have never designed an abstracted API like this, so I understand if this kind of feature request is not the direction you want to take the API).