fixed jspm imports in sass files for most environments (i.e. cordova)

src/resolve-path.js

@@ -10,11 +10,9 @@ async function resolvePath(request) {
     current = current.replace(/^jspm:/, '');
     if (!current.match(/\.s(c|a)ss/)) current += '.scss';
     // we need the parent, if the module of the file is not a primary install
-    let parent = `${System.baseURL}${request.options.urlBase}`;
-    // when adding urls, some unwanted double slashes may occur
-    if (System.baseURL.slice(-1) === '/' && request.options.urlBase.slice(0, 1) === '/') {
-      parent = `${System.baseURL}${request.options.urlBase.slice(1)}`;
-    }
+    const parentURL = url.parse(System.baseURL);
+    parentURL.pathname = request.options.urlBase;
+    const parent = url.format(parentURL);
     const file = await System.normalize(current, parent);
     return file.replace(/\.js$|\.ts$/, '');
   }

test/resolve-path-test.js

@@ -70,7 +70,7 @@ describe('resolve-path', () => {
     const request = {
       current: 'jspm:indirect-package/mock-asset',
       previous: 'stdin',
-      options: { urlBase: '/jspm_packages/npm/mock-package@1.0.0/' },
+      options: { urlBase: url.parse(`${__dirname}/jspm_packages/npm/mock-package@1.0.0/`).path },
     };
     const p = await resolvePath(request, '/');
     // System.normalize in resolvePath will give us the absolute path