Fixes the namespace definition which had too many closing braces on APPLE devices

Modernises the codebase from nested workspaces to modern form. E.g.:

namespace A{
namespace B {}
}

Becomes
namespace A::B{
}

This will allow us to specify in the coding standards to prefer the
simple form instead

Also updated class_maker.py

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 #15271

LoadInstrument algorithm now uses OptionalBool. MandatoryValidator used and tests for that class have been fixed.

I don't think this method is used anywhere, which is a good thing as it
was returning a pointer to a temporary.

It makes no sense for some property types (bool, string) and is
only used once.

MultiFileProperty changed to store a vector of vectors of file names. File
names that share a vector are to be added. Old functionality can be produced
by calling "flattenFileNames".  See source code for more info.

MultiFileProperty was used in one place previously (MDMergeFiles), this has
been modified to relect these changes.

Load now implemented in terms of MultiFileProperty, though its interface is
unchanged.  "Filename" input is now parsed as a multi file, and if that
fails old functionality is attempted.  Error reports will output the result
of both attempts.

Some additional template specialisations / "toString" overloads
surrounding the Property class heirachy were necessary to properly support
std::vector<std::vector<std::string> >.

Changed from an INTEL to a APPLE ifdef

Refs #3175. Move the macro for defining IPropertyManager::getValue functions to the header so that all user-defined types can access it. Also implement a test for MatrixProperties being passed to algorithms. We have one problem now with this kind of code: DblMatrix R = getProperty("R"). IPropertyManager can't define a template conversion operator because Visual Studio has a problem with the std::string version that even a specialization doesn't cure.

Modify the SolidAngle calculation for cylinders to EXCLUDE the end caps so that it closely approximates the effects of shadowing for stacked cylinders. Also cleaned up some indentation in renderinging code and made an error message clearer in IPropertyManager. Re #2596

Fix the mac build. The intel compiler defines size_t to unsigned long which doesn't match uint64_t that was exported. Re #3008

Refs #2751: Added stub for Fake MD data algorithm. Made properties report the type they expected when you give the wrong value.