Skipping LineNumberNodes in v0.7 macros

A for loop won’t suffice, you need to go recursively into the ASTree to access all possible comments. This is why Reduce.linefilter is recursively defined with while loops

https://github.com/chakravala/Reduce.jl/blob/master/src/parser.jl#L423-L443

This is backwards compatible with 0.6 and 0.7 simultaneously.