[test] fortran OKL links

[test] All 315 tests successful: C, Fortran @ CPU, GPU, OpenCL, OpenMP

[okl] pointer arith & cleanup

[occa] t10 output & OpenCL backend

[occa] wip qfunction t30, ex1-volume-annulus

[occa] qfunction t20 cpu + gpu

[occa] CeedQFunctionApply_Occa kernel wip

Merge branch 'master' of https://github.com/CEED/libCEED

starting to add magma backend; just putting the infrastructure for now ...

[occa] QFunction from OKL files

[occa] Remove unnecessary atomicAdds in the OKL kernels

[OpenMP] Add omp backend for the tests

[make] tst, prv targets

[test] t01-vec-f ceedvectorrestorearrayread call fix

t20-qfunction-f: comment dummy argument

Enumerate QFunctionFortranStub call with arguments

Replace %val(0) by ceed_null

Update Nek5000 example

and remove some whitespaces.

Fix a bug in Fortran interface

and finist t30-operator test in Fortran

Add t30-operator-test and fix a few errors

on C side

Add test t30-operator-f

Fix the QFunction interface of Fortran

and add t20-qfunction-f

Update the tests with a subroutine separator

Add t14-basis-weight test

Add t13-basis-f.f and Fix a memory bug

when freeing dicts