Doubles, more customization, auto-scaling min/max

• Moved to using doubles instead of floats
• Auto-scaling y axis' min/max
• Customizing legend values
• Controlling extra offsets caused by the legend
• Negative values in stacked bar charts
• Word wrapping in pie chart's center text
• Word wrapping in "below" legends
• Support for multi-line text in x-axis
• Better cooperation with scrollviews (Bar/Line charts automatically, Pie/Radar charts through enabling two-finger rotation in pie chart)
• Viewport support for max scale on x axis
• Many other small features
• More bug fixes