Group names with a common prefix are collapsed and expanded incorrectly

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Use a table with some groupings that start with the same prefix (e.g. 
"Colors", "Colors Alt", "Colors Additional").
2. Click one of the columns to expand the group.
3. Notice all the columns with names starting with "Colors" are expanded. 

What is the expected output? What do you see instead?
Only the group clicked on should be expanded

What version of the product are you using? On what operating system?
DataTables.RowGrouping  1.2.9
Mac OS X 10.10
Chrome

Please provide any additional information below.
in the two functions fnExpandGroup() and fnCollapseGroup() the group selectors 
are as follows:
$("td[data-group=^'" + sGroup + "']").removeClass("expanded-group");
$("td[data-group=^'" + sGroup + "']").addClass("collapsed-group");
Our fix was to change these to:
$("td[data-group='" + sGroup + "']").removeClass("expanded-group");
$("td[data-group='" + sGroup + "']").addClass("collapsed-group");

Original issue reported on code.google.com by dan.jonw...@gmail.com on 10 Mar 2015 at 2:11