Additional visualizations

[KMouratidis]

These should probably be implemented in one place and in an abstract manner so that they can be used anywhere within the app.

1. More chart types (e.g. from plotly):

• [x] Scatter plots
• [x] Line plots / Time series
• [x] Histograms / Bar charts
• [x] Pie chars
• [x] Bubble charts
• [x] Filled area plots
• [x] Error bars & Confidence / prediction intervals
• [x] Heatmaps
• [x] 2D density plots
• [x] 3D charts
• [x] Pairplots
• [x] Graphs / Networks (e.g. cytoscape, networkX, visdcc)
• [x] Maps
• [ ] Tree maps
• [ ] Candlestick / OHLC charts
• [ ] Trees
• [ ] Dendrograms

2. Add aggregations to plots:

• [ ] groupby
• [ ] filter
• [ ] count
• [ ] mean / median / min / max / sum