Also updated class_maker.py

Signed-off-by: Harriet Brown <harriet.brown@stfc.ac.uk>

This commit replaces all header guards in API with #pragma once

Update copyright headers in all files

Squashed commit of the following:

* First version of a script to manage copyright statements

re #23468

* Neatened up script, added comments

re #23488

* move script to tools directory

re #23488

* small script changes and a couple of manual file changes

re #23488

* Minor chnage to whitespace detection in regex

re #23488

* Add an excluded directory

re #23488

* remove a repeasted copyright statement in a file

re #23488

* Don't comsume the comment end if it is on the same line

re #23488

* fix error in new copright parsing

re #23488

* remove double copyrifght entry

re #23488

* Improve handling of old copyrights at the start of comments

re #23488

* remove empty comments re #23488

* exclude gsoapgenerated directories

re #23488

* Sort out greedy line matching re #23488

* improve empty comment removal

re #23488

* improve false positives

re #23488

* impressive speedup by limiting regex matching length

re #23488

* remove evil invisible non ascii character

Also upadte the copyright at the same time

re #23488

* resolve multiple copyrights in a single file

re #23488

* resolve an issue with new statement detection

re #23488

* another unprintable unicode character

re #23488

* pep updates and cmake the new copyright fit clang format

re #23488

* update already done new format headers

re #23488

* wrong type of bracket

re #23488

* Update class_maker and friends

re #23488

* Update all copyright statements

re #23488

* clang format re #23488

* flake8 warnings re #23488

* Flake8 warnings re #23488

* Exclude .cmake.in and rb.in files

re #23488

* replace missing line re #23488

* exclude .py.in files as they are flasely recognized as C++

re #23488

* another setp.py.in re #23488

* another .py.in correction re #23488

* Hopefully the last of the .py.in files re #23488

* resolve utf-8 encoding of python files and changed ABINS checksum

re #23488

* updates to unit tests that reference line numbers

re #23488

* remaining unit test files and other fixes

re #23488

Refs #9435

Refs #9435

Also start fixing a bug whereby the cluster offsets can become larger than the range of an integer. This has been partially fixed by better calculating the number of possible clusters that could exist. The full fix should be to also change the type of m_id in DisjointElement from int to size_t!

Another issue that is being worked on here is a faster clone of the MDWorkspace. We only care about it's shape, so we just need something the right size to start putting data into!

Lots of work still to do yet. But on some basic tests generates expected
component images (MD workspaces). One thing that will need to be solved
yet, is what strategy for background detection to use. Also speedups will
be required across the board.

but users might use it too. Wanted to make a separate ticket for this but trac is down

Refs #3724: Pulled wiki description text from the wiki site and added in algorithms' header file with special tags. The auto_wiki.py script can retrieve the text to generate the wiki page fully.

Refs #3507. Full-move to MVP. Sorry for large checkin, but these things are all dependent and cannot have partially working GUI code.

Refs #3157 Sort our System.h. It was becoming a dumping ground. It should only be touched when absolutely necessary as it affects every file in Mantid. Also combined this with Refs #2345 to sort out DLLExport/DLLImport usage. It's done for Kernel, Geometry and API but stuff in the plugins could do with updating as well.

Do away with MantidPlotReleaseDate.h and have everything in MantidVersion. Turn MantidVersion into a class with static functions so that the part that changes every time can go in a cpp - this means files that include MantidVersion.h (e.g. the enormous ApplicationWindow.cpp) don't get compiled every commit. Re #2722. Also formats date better, which fixes #2246.

Rename Framework code directory to just that. Also delete Main and VS & Eclipse project file. Re #1881.

Copyright updated to read
Copyright © 2007-10 ISIS Rutherford Appleton Laboratory & NScD Oak Ridge National Laboratory

Allow empty value in ListValidator if it's on the list of allowed values plus a bit of tidying up in the validators.
Re #501.

There are changes to WorkspacePropertys that affect PropertyManager.  In all cases Property.setValue() now returns a string containing any validation errors.  This is a change to the WorkspacePropertys that sometimes ignored errors.  There are descriptions for some propertys in MantidPlot available as a tooltip re #593 and re #410