Set MinPointLength for Rating Distribution chart

related/parent Issue : https://appirio-community.force.com/cmc/a3v50000000I9rz
currently Rating Distribution show same bar for 0 - 20, no difference (invisible) since the higher value >= 5k
current : http://screencast.com/t/Hrzj9fVUQ
fixed : http://screencast.com/t/0bh69MkB

i got solution from http://highcharts.uservoice.com/forums/55896-general/suggestions/3891296-add-minpointlength-for-close-to-zero-values-but-no