disabled zoom during brushing
zoom changes

Conflicts:
	src/coordinate-grid-chart.js
further experimentation with zoom implementation
overhauled zoom-related behaviors to fix issues documented at https://github.com/NickQiZhu/dc.js/wiki/Zoom-Behaviors-Combined-with-Brush-and-Range-Chart
de-linted
reverted accidentally committed build artifacts
added note on zooming to brushing docs
Merge pull request #402