Merge branch 'canvas' of https://github.com/clocksmith/dygraphs

diff --cc dygraph-layout.js
index 85a4bcb,699b444..4beddc4
--- 1/dygraph-layout.js
--- 2/dygraph-layout.js
+++ b/dygraph-layout.js
@@@ -141,11 -146,10 +146,12 @@@ DygraphLayout.prototype._evaluateLineCh
      var prevYPx = NaN;
      var currXPx = NaN;
      var currYPx = NaN;
+     var setPointsLength = 0;
  
      // Ignore the pixel skipping optimization if there are error bars.
 -    var skip_opt = (this.attr_("errorBars") ||
 +    // XXX 2011-07-25 temporarily disabled (see autotests/tests/selection.js)
 +    var skip_opt = (true ||
 +                    this.attr_("errorBars") ||
                      this.attr_("customBars") ||
                      this.annotations.length > 0);