Add option to keep angles fixed, to FindUBUsingLatticeParameters

[mantid-builder]

This issue was originally TRAC 4563

Original Reporter: @DennisMikkelson

Since the unit cell angles are often known exactly, an option should be added to the FindUBUsingLatticeParameters algorithm to use the exact angles specified by the user, rather than allowing them to vary. A Boolean property should be used to control whether or not the angles can be varied.

[mantid-builder]

@NickDraper (2012-04-30T14:12:55):
Moved at end of release 2.1

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@NickDraper (2012-08-10T12:43:37):
Moved at the end of release 2.2

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@NickDraper (2012-10-28T11:38:49):
Moved to milestone 2.4

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@NickDraper (2013-04-29T09:49:39):
Moved to r2.6 at the end of r2.5

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@NickDraper (2013-07-26T13:54:58):
Moved to backlog at the code freeze for R2.6

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@NickDraper (2014-02-14T11:04:56):
Bulk move to assigned at the introduction of the triage step

[NickDraper]

This is not one of the mainly used FindUB's archived for now