Fixed the operation.call() syntax

This pull request contains the latest cmd syntax patches from the [rdt-next-snrkiwi-add-send+cmd-to-scriptfunction](https://github.com/psoetens/rtt/tree/rdt-next-snrkiwi-add-send+cmd-to-scriptfunction) branch and one new commit that fixes the `.call()` syntax as already discussed. The goal is to merge your master-introduce-v1cmd-syntax to master sooner or later.

We should also consider to merge some other bug fixes related to scripting from the rdt-next branch to master before the toolchain 2.8 release:
- https://github.com/psoetens/rtt/commit/8d215d3b21366dd8c216d7a5b19836546853222f scripting: allow parsing of keywords at the end of a parse string.
- https://github.com/psoetens/rtt/commit/6537ae7736ba887c25642f76ac96081d04039c5e scripting: protect FSM execution and tracing against self-deactivation
- https://github.com/psoetens/rtt/commit/00b26794c31051b6710ccf7bad1ea393a9ebb6ca scripting: first check if we are still loaded before we try to remove ourselves