add chartOutput as alias to be consistent with Shiny.
rename Polychart class to Polycharts
refactor by moving lib logic to rCharts parent class.
move utils.R to top and modify filenames for consistency.
fix examples for leaflet and xcharts.
Fixes #62
add metadata to morrisjs examples
modify Leaflet chart template
add more examples for Leaflet
remove nvd3Plot from class of chartdiv
update Leaflet.R with new features.
bump version to 0.2.6