Enable message folding in fatalError

[Mikolaj-A-Kowalski]

Changes the fatalError subroutine to something presentable. Resolves #33

• error messages will be printed to STDERR.
• the error message will be folded to respect MAX_COL parameter.
• uses error stop which will produce backtrace on some compilers

For example, a long error message will look as follows:

<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
Fatal has occurred in:
bestfunction (worstfile.f90)

Because:
This is a very long error message which will contain some number of
detail a person may find interesting and useful for debugging.
Although I have no clue how to build such long strings in a nice way
in Fortran. But sometimes it may be immpossible
sinceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee long strings do happen.
                                                          Also a lot
of whitespace will look weird
<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
ERROR STOP

Error termination. Backtrace:
#0  0x7f093ce2cbd0 in ???
#1  0x7f093ce2d685 in ???
#2  0x7f093ce2e9f3 in ???
#3  0x55ad47fd29dd in __errors_mod_MOD_fatalerror
   at /home/<user_path>/SCONE/SharedModules/errors_mod.f90:57
#4  0x55ad47fcb94e in scone
   at /home/<user_path>/SCONE/Apps/scone.f90:24
#5  0x55ad47fcb7be in main
   at /home/<user_path>/SCONE/Apps/scone.f90:3

In the anticipation of the warning log the function was also moved to a new errors_mod module.

[valeriaRaffuzzi]

Is this enough for compatibility with all the functions that call fatalError and have 'use genericProcedures' rather than 'use errors_mod'?

[Mikolaj-A-Kowalski]

Yes. Basically the import makes the fatalError available in genericProcedures scope and use genericProcedures import the entire scope including things that were imported.
Actually this is a feature of Fortran one needs to be careful about since this is how something can sneak into a scope unknowingly.

That being said we should use errors_mod directly. I just wanted to avoid horrible conflicts with other PRs.

[valeriaRaffuzzi]

I see. I also think using 'use errors_mod' directly would be cleaner, even though this means changing a lot of files. Worth creating an issue I assume!

[valeriaRaffuzzi]

I think this looks great, thanks for writing this!

[Mikolaj-A-Kowalski]

Thanks for the review! If it is good to merge for you: please do the honours