Function Check/postprocess: improve documentation
@values: if a @default_value is defined, use this as fallback value
@default_other: clear @default_other with empty value
Default 'josm': *-linecap by default is 'round'; 'butt' when dashes is set
Merge pull request #56 from plepe/56-josm-dashes-linecap

JOSM: *-linecap by default is 'round'; 'butt' when dashes is set