Implement toTuple and custom functions for toAny and pushAny

[axdank]

• parse tuple struct type
• Use custom function ziglua_toAny or/and ziglua_pushAny for special cases, like when working with extern structs and others.

[natecraddock]

@VisenDev could you take a look at this?

[VisenDev]

@natecraddock where are we at on this pr?

[natecraddock]

@VisenDev looks like this might have merge conflicts

Sorry for the long delay

[robbielyman]

merge conflicts fixed :)

[VisenDev]

looks good!