feat(events): Add events to reactiveMixins

[apertureless]

This will resolve #382

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Added some vue events to the mixins based on different actions.

• chart:render - if the mixin performs a complete rerender
• chart:destroy - if the mixin deletes the chart object instance
• chart:update - if the mixin performs an update instead of a re-render
• labels:update - if new labels were set
• xlabels:update if new xLabels were set
• ylabels:update - if new yLabels were set

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todo

• update docs
• update tests