Update underscore dependency to 1.6.0
Rename ChartView's dimensions property: .dimensions -> .dims
Change ChartView to expect options.dims to be an actual ChartDimensions instance
Change ChartDimensions to be a backbone model with function properties for its dimension properties (where some are just attr accessors and others are computed from others)
Change ChartView to resize and retranslate itself when its dimensions change
Rebuild vendor script
Merge branch 'feature/issue-130-more-dynamic-chart-dimensions' into develop