Merge pull request #239 from dandehavilland/rollout-callback

Added rollout_callback, inverse of rollover_callback
Moving deprecation test to data_graphic tests
Bars displaying correctly
Predictors & rollovers; Added page for testing (WIP)
Added basline for vertical charts
clearing unused options from the example
Correcting bar spacing, label positions
Fixing syntax error
Allow y axis labels to be formatted
Following the rules for contrib
Fixing y axis to take predictor and baseline into account
Adding text truncation for vertical bar labels
Added 'animate_on_load' to bar charts
Animating/Transitioning bars, predictors and baselines; Refactored plotting
Fixing double transition on horizontal bars; load animation now fires correctly