Convert REF_L to use RectangularDetector

[Peter Peterson]

As an upgrade to the existing REF_L geometry switch to a RectangularDetector. An example for REF_M is below

<instrument xmlns="http://www.mantidproject.org/IDF/1.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.mantidproject.org/IDF/1.0 Schema/IDFSchema.xsd" 
 name="REF_M" valid-from="1900-12-08 11:36:21.935542" 
                                             valid-to="2100-01-31 23:59:59"
                                             last-modified="2011-12-08 00:00:00">
  <defaults>
    <length unit="metre"/>
    <angle unit="degree"/>
    <reference-frame>
      <along-beam axis="z"/>
      <pointing-up axis="y"/>
      <handedness val="right"/>
    </reference-frame>
    <components-are-facing x="0.0" y="0.0" z="0.0" />
  </defaults>
  <!--SOURCE AND SAMPLE POSITION-->
  <component type="moderator">
    <location z="-18.703"/>
  </component>
  <type is="Source" name="moderator"/>
  <component type="sample-position">
    <location x="0.0" y="0.0" z="0.0"/>
  </component>
  <type is="SamplePos" name="sample-position">
    <cuboid is="sample-shape">
      <left-front-bottom-point x="-0.001" y="-0.01" z="-0.01"/>
      <left-front-top-point x="-0.001" y="0.01" z="-0.01"/>
      <left-back-bottom-point x="-0.001" y="-0.01" z="0.01"/>
      <right-front-bottom-point x="0.001" y="-0.01" z="-0.01"/>
    </cuboid>
    <algebra val="sample-shape"/>
  </type>
  <!--MONITORS-->
  <!--DETECTOR-->
  <component type="wire2d"  idstart="0" idfillbyfirst="y" idstepbyrow="256">
    <location r="2.5505" t="0." p="0." name="BNLDetector"/>
    <parameter name="t-position">
      <logfile id="DANGLE" extract-single-value-as="mean" eq="3.5-value"/>
    </parameter>
    <facing x="0.0" y="0.0" z="0.0"/>
  </component>
  <type name="wire2d" is="RectangularDetector" type="pixel" 
        xpixels="304" xstart="-0.1064" xstep="+0.0007"
        ypixels="256" ystart="-0.896" ystep="+0.0007" >
  </type>
  <type is="detector" name="pixel">
    <cuboid id="pixel-shape">
      <left-front-bottom-point x="-0.00035" y="-0.00035" z="-0.0005"/>
      <left-front-top-point x="-0.00035" y="0.00035" z="-0.0005"/>
      <left-back-bottom-point x="-0.00035" y="-0.00035" z="0.0005"/>
      <right-front-bottom-point x="0.00035" y="-0.00035" z="-0.0005"/>
    </cuboid>
    <algebra val="pixel-shape"/>
  </type>
</instrument>

[Nick Draper]

Moved to R3.5 at the R3.4 code freeze

[Stuart Campbell]

This ticket has been transferred to github issue ​11912