Link to PLUGINS.md
Merge pull request #1127 from brianpeiris/patch-1

Link to PLUGINS.md
Clip the pie center only when using offset auto.

If an explicit numeric offset was provided, we should not override it.
The clipping is only meant to apply to the case where the center is
moved to make room for the legend in 'auto' mode, anyway.
Prevent options from becoming global.

The pie plugin was a little too clever in its use of closures.  In
processDatapoints it set canvas, target, and options for use in other
functions.  Since options was not declared this meant that it became
global.  Pages containing multiple pie plots therefore saw a range of
weird effects resulting from earlier plots receiving some of the options
set by later ones.  Resolves #1128, resolves #1073, resolves #1055.
Also stop at root when extracting CSS color

This change adds an additional check for whether the parent element
is `null` or `undefined` in `$.color.extract`.  This can happen when
working with elements that have not yet been added to the DOM under
`<body>`.

Consider the following example pie chart.

    var elm = $("<div />")
      .css({
        width: "240px"
      , height: "320px"
      })
    var data = [
      {label: "One", data: "33"}
    , {label: "Two", data: "33"}
    , {label: "Three", data: "33"}
    ]
    var opts = {
      legend: {
        show: true
      }
    , series: {
        pie: {
          show: true
        }
      }
    }
    $.plot(elm, data, opts)
    elm.appendTo($("body"))

When flot inserts each legend row, it tries to use the same color as
the corresponding graph part, unless it was explicitly specified in
the options.  However, in this example, `$.color.extract` runs into
an unexpected `null` reference because `<body>` is not an ancestor
of `elm`.  Specifically, a `TypeError: Cannot read property
'nodeName' of undefined` would be thrown.
Fix version branch name and clarify spaces v.s. tabs.
Prioritize pull request instructions for clarity.
Merge pull request #1084 from execjosh/stop-also-at-root-element

Also stop at root when extracting CSS color
Slight cleanup / optimization for #1084.