array was allocated, but not cleaned up before use.
I now set the buffer to zero.

also add easier control of template double for if.
this way i can compile faster if i need to

use omp_get_max_threads outside parallel environment, not
omp_get_num_threads (which is 1).

when using unique_ptr for arrays, they are cleaned up by calling
`delete[] bla.release()`.
At least, cppreference says that the release method
"returns a pointer to the managed object and releases the ownership ".
https://en.cppreference.com/w/cpp/memory/unique_ptr

I think it's more obvious when we talk about "index of component" and
"index of variable" what is meant, rather than having "FIELD_IDX" and
plain "IDX".

We will never use AdamsBashforth with more than 10 steps.

Ensure that the limit will not be included in the interval -- Add an assertion if a dead lock will appear

Debug -- add default value for cutoff and options -- use different tag values to be idle if missmatch