Re: `import foo {.private.}` to allows access to private fields (eg: package-level visibility)

[timothee]

well nim files are not header files unlike C, C++ (or D's interface di files, 
which we could think about in nim but that's a separate discussion), so I'm not 
sure how one could avoid rebuilding main.nim if it imports foo.nim and foo.nim 
changes only its private procs ; eg foo could define a public template that 
call private procs. In any case, even if above rule was feasible, that's not 
really a concern since a import foo {.private.} would just be instructed to 
rebuild in case foo is modified, because of the {.private.}