new rule: imports, globals and persistent before code

[niklasnylen]

What kind of feature is this?

• New feature in MISS_HIT

MISS_HIT component affected

• Style checker

Describe the solution you'd like
Global and persistent variables shall be declared first in functions.

[florianschanda]

However they need to be after any argument validation blocks, so a function should be ordered like this:

1. Argument validation blocks (only in matlab 2019b)
2. imports
3. global
4. persistent
5. function body
6. nested functions

[florianschanda]

@niklasnylen an update this ticket (and similar ones that would do code re-structuring beyond adding whitespace and deleting stuff).

I plan to create another tool mh_reformat that is a much more advanced code reformatting tool. It does not produce messages like mh_style; but instead just pretty prints code.

I suspect I will also remove the autofixing from mh_style once this works. In the future mh_style will only complain :)

The reason for this is largely technical / and developer (i.e. me) sanity. The code that does the fixing has become so complicated that adding new functionality is just not practical any more. :/