Update screen reader (& data reader) tool to output values (& error?)

[NickDraper]

This issue was originally TRAC 857

At the moment the screen reader (& data reader) tool displays the X and Y axis position, for 2D plots from Mantid Matrices it should also display the Y value (counts) and Error value.

Also add the following functionality when double clicking with the data reader tool. Add a dot (reverse of colour map colour) and label (black) to the point clicked with values. Also open a table and add a row with the values selected (x,y,counts,e). Selecting several points should add rows to the same table.

[NickDraper]

@NickDraper (2010-12-16T09:49:13):
Bulk move of tickets to iteration 27, if your ticket is essential for Iteration 26 then move it back.

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@NickDraper (2011-02-15T09:09:35):
Bulk move of tickets at the end of iteration 27

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@NickDraper (2011-04-27T07:36:05):
Bulk move of tickets at the end of iteration 28

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@NickDraper (2011-06-10T13:22:28):
Taken from Sofia Antony's list after she left

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@NickDraper (2011-06-27T08:20:29):
"New" tickets moved at the code freeze of iteration 29

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@NickDraper (2011-09-19T09:31:04):
Bulk move of tickets to iteration 31 at the iteration 30 code freeze

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@NickDraper (2012-01-09T09:45:04):
Moved to iteration 33 at iteration 32 code freeze

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@NickDraper (2012-04-30T14:15:56):
Moved at end of release 2.1

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@NickDraper (2012-08-10T12:45:18):
http://www.mantidproject.org/Release_Notes_2_2_Full_List

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@NickDraper (2012-10-28T11:42:48):
Moved to release 2.4

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@NickDraper (2013-01-28T09:25:16):
Moved at the code freeze for release 2.4

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@NickDraper (2013-04-29T09:50:12):
Moved to r2.6 at the end of r2.5

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@NickDraper (2013-07-26T13:59:12):
Moved to the Backlog after the code freeze for R2.6

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@NickDraper (2014-02-14T11:07:58):
bulk move to assigned at the into of the triage step

[NickDraper]

This is no longer required