Function parse_swc_lines 

pub fn parse_swc_lines<R: BufRead, S: StructureIdentifier>(
    reader: R,
) -> impl Iterator<Item = Result<SwcLine<S>, SwcParseError>>

Parse lines from a SWC file.

Skips blank lines and treats all #-prefixed lines as comments. Does not check the neuron for consistency, but does check for valid structures.