Improve response of idstepbyrow attribute of an IDF rectangular_detector

[Anders Markvardsen]

Take the example

<component type="panel" idstart="10001" idfillbyfirst="y" idstep="1" idstepbyrow="19">

<location z="11.93" name="multi-detector"/>

</component>

<type name="panel" is="rectangular_detector" type="multi-detector-pixel"

xpixels="40" xstart="-0.044" xstep="+0.0022" ypixels="46" ystart="0.0" ystep="+0.0022" > <properties/>

</type>

where idstepbyrow is set to 19 less than or equal to the number of detector in the y-direction, which is 46. Result of this is first row of y-detectors are assigned to det IDs: 10001 to 10046, then for the next row it attempts to start from 10001+19 and struggles because each detector must be assigned a unique ID.

Change this so that warn the user if idstepbyrow too small and then re-assign idstepbyrow = actually number of y-detectors.

[Anders Markvardsen]

(In [11918]) Fix to re #2905

[Anders Markvardsen]

Ups embarringly just realising that the above ticket is invalid since if it was implemented we couldn't handle the situation in e.g. sand2d...:

<component type="detector-bank" idstart="2000000" idfillbyfirst="y" idstep="1000" idstepbyrow="1">

<location x="1.1" z="23.281" name="front-detector"/>

</component>

[Anders Markvardsen]

(In [11919]) Realising that I was doing something stupid with regards to re #2905

[Anders Markvardsen]

Ignore this ticket it was bonkes from the start

[Nick Draper]

Everyone has the right to create one "bonkes" ticket

[Stuart Campbell]

This ticket has been transferred to github issue ​3752