Address error in destroy method for pie chart.
Update charts unit tests.
Address issue in which multipe node reference were created for a tooltip. Address issues with orphaned text in ie6, 7, 8. Fix #1285. Fix #1293"
	modified:   js/ChartBase.js
Addressed issue with leftover text nodes in chart's legend. Addressed edge cases with leftover tooltip contents in chart.
    modified:   js/CartesianChart.js
	modified:   js/ChartBase.js
	modified:   js/ChartLegend.js
Clean up chart's series-tests unit test for ie.
	modified:   tests/unit/assets/series-tests.js
Remove unused variable from CartesianChartLegend.
	modified:   js/CartesianChartLegend.js
Add destructor method to PieChart. Fix #1139.
	modified:   js/PieChart.js
Merge branch 'issue1139' into dev-3.x
Charts build files.
	modified:   ../build/charts-base/charts-base-coverage.js
	modified:   ../build/charts-base/charts-base-debug.js
	modified:   ../build/charts-base/charts-base-min.js
	modified:   ../build/charts-base/charts-base.js
	modified:   ../build/charts-legend/charts-legend-coverage.js
	modified:   ../build/charts-legend/charts-legend-debug.js
	modified:   ../build/charts-legend/charts-legend-min.js
	modified:   ../build/charts-legend/charts-legend.js
	modified:   ../build/series-base/series-base-coverage.js
	modified:   ../build/series-base/series-base-debug.js
	modified:   ../build/series-base/series-base-min.js
	modified:   ../build/series-base/series-base.js
	modified:   ../build/series-pie/series-pie-coverage.js
	modified:   ../build/series-pie/series-pie-debug.js
	modified:   ../build/series-pie/series-pie-min.js
	modified:   ../build/series-pie/series-pie.js