Update "register_driver"

[LeonidVas]

Changes of patchset:

• Double definition of the "register_driver" method has been removed
• Loading core drivers of the queue has been moved from abstract.lua to init.lua
• Added check for driver overriding
• Added description of the "register_driver" method
• Driver API description has been fixed
• Added description of the "touch" driver API method

ChangeLog:

• Check for driver overriding added. Previously, such check existed only for the core drivers in the case of a delayed start (when the queue module tried to initialize before the box configuration.).
• Description of the "register_driver" method was added.
• Description of the "touch" driver API method was added.

[LeonidVas]

Thank you!

LGTM, but minor comments:

Regarding _'refactoring: update definition of "registerdriver" method'. AFAIU the commit does not change a behaviour, but it adds a test. It is not clear on the first glance, whether something is fixed or not. I would clarify this point.

Tests were added to increase the tests coverage, so as not to break something during refactoring.

Regarding 'refactoring: move loading core drivers to init.lua'. It seems it is not just refactoring, because it actually changes a behaviour: the check re name clash against built-in drivers now occurs at require('queue') moment despite whether box is confgured or not. I don't know, how to better reflect this fact: remove 'refactoring' prefix or just note the difference in the behaviour in the commit message. I tends to interpret 'refactoring' as 'no actual behaviour changes', but maybe 'there are behaviour changes, which aren't the main reason of changes' is okay too (not sure).

'refactoring' prefix has been removed.

[LeonidVas]

It was here before, but was missed in some cases. I would try to give exact case(s), where user-visible behaviour is changed. Please, try to describe it in a more explicit way, but feel free to ignore this comment if the description will became vague (sometimes it is hard to give an idea in tight words).

ChangeLog updated.