Merge pull request #133 from forio/documentation

mbean comments re cartesian being unclear
updated doc build
Added ability to disable tooltip marker rendering
FNM-79: Fixed chart name from pie series to donut series and styled column chart
Added default for enabling tooltips
Fixed opacity on line chart markers when animation is turned off
Fixed rendering of non-stacked area charts with negative data

Fixes #134
Fixed tooltip classes and enabling option
namespace variable definition correctly
Removed specificity in color definitions
Renamed and scoped some less variables to prevent collations with bootstrap
Fixed 'half-pixel' rendering for area charts
FiFixed 'half-pixel' rendering for bar charts
FiFixed 'half-pixel' rendering for column charts
FiFixed 'half-pixel' rendering for line charts
Adjusted half pixel rendering for bar charts
Fixed half pixel rendering for column charts
Fixed negative values rendering for bar charts
build documenation placeholders
added basic description of tooltip.enable config option