Charts: Upgrade to Flot 0.8.1

- 100 percent pie charts fixes #2532
- Added responsive charts but not for pie charts
- fix for the non working pie hover issue. Separated the image container and the flot placeholder
- Chart pie working example - Re-organizing the pie chart and documented the know trivial bug, white inner circle in a pie chart.
- Applied changes on "eng/fra" to "en/fr" file name
- add flotCanvas.js to ignore list

Fixes gh-2578
Closes gh-2840