Use placeholder dimensions instead og canvas dimensions in calculations which fixes draw bug after introducing Retina support in Flot core

Removed implicit global variables in threshold plugin.

Cleaner and portable function to get pixelratio.

This patch is intended the make getPixelRatio function portable and cleaner :)

Previous indentation issue has also been fixed.

Thanks :)

Support different border color and widths for each side of the chart.

Edited grammatical error.

Added Szymon Barglowski, who originally reported the fmt variable.

Prevent insertSteps and fmt from becoming global.

`fmt` was being hoisted as a global variable.
Signed-off-by: Nick Campbell <nicholas.j.campbell@gmail.com>

Locally declared insertSteps by adding var s.t. it would no longer be a
global variable.
Signed-off-by: Nick Campbell <nicholas.j.campbell@gmail.com>

Added options to customize tilted pie shadows.

Fix makeCanvas for IE, broken by Retina support introduced in 179d2e1d.

Fixed a typo.

Update links to point to flotcharts.org.

Fix typo

Project links have changed.

Cast tick label to string prior to `replace` call

In the edge case that an actual integer, or other non-string, is passed as a label, it must be cast to String before `replace` can safely be called.

The recent changes to add retina support included a call to getContext
made before excanvas/flashcanvas had a chance to register their hooks;
fixed by moving that code up a few lines.

- Minor code cleanup and comments describing how we use pixel ratios.