Merge pull request #1 from NickQiZhu/master

rebasing my fork
Box plots with no data no longer attempt to draw with NaN values at the top of the graph
Refactored boxplot NaN fix not to use public preRedraw listener + disabled elasticX by default
Pushed line chart specs testing coordinate grid mixin functionality into coord spec. Removed equivalent bar chart tests.
Merge pull request #458 from pivotalforks/bar-chart-test-to-spec

Coordinate grid / line chart spec refactoring
Merge pull request #445
added option to enable brush rounding for centered bar chart
updated fluctation and volume charts to always use rounding
cleaned up docs
Merge remote-tracking branch 'upstream/master'
added optional right aligned title label to rowChart. _chart.renderTitleLabel
Merge pull request #462
Merge pull request #459