Add a LuaForce.research_queue function

[Muppet9010]

The new LuaForce.research_queue would expose read/write access to the forces current research queue as a numbered dictionary of technologies. With number 1 being the current research and counting up the queue.
When read it would return LuaTechnology and when writing it would accept TechnologySpecification. Same types as previous_research and current_research.

This would allow mods to identify (read) future scheduled researches in the queue and to manipulate them if desired.

[Bilka]

Okay, added to the next version.

Note for mod makers: I have removed the LuaForce::current_research write in the next version, you will have to use LuaForce::add_research() and cancel_current_research() instead (those are added by the next version). This change was made because the current_research write did not work correctly with the research queue.

[Muppet9010]

thanks, works as expected