feature(importer): support underscore in @import file name for partials
feature(importer): support underscore in @import file name for partials

Sass will automatically translate partial files with an underscore but the try catch block checks for file on the system that is an exact match of the provided file name. To allow for the use of underscore interpolation the try catch block needed a nested try for checking for a file with an underscore

Fixes #1

AndreSteenveld/node-sass-jspm-importer,idcware/node-sass-jspm-importer