add @resolver.import

package.json

@@ -48,6 +48,7 @@
     "remix-tests": "0.1.1",
     "remixd": "0.1.8-alpha.6",
     "request": "^2.83.0",
+    "@resolver-engine/imports": "^0.3.0",
     "rimraf": "^2.6.1",
     "selenium-standalone": "^6.0.1",
     "solc": "^0.5.0",

src/app/compiler/compiler-imports.js

 'use strict'
 var base64 = require('js-base64').Base64
 var swarmgw = require('swarmgw')()
+var resolver = require('@resolver-engine/imports').ImportsEngine()
 var request = require('request')
 
 module.exports = class CompilerImports {
@@ -112,13 +113,19 @@ module.exports = class CompilerImports {
         })
       }
     })
+    if (found) return
 
-    if (found) {
-      return
-    } else if (/^[^:]*:\/\//.exec(url)) {
-      cb('Unable to import "' + url + '": Unsupported URL schema')
-    } else {
+    resolver
+    .resolve(url)
+    .then(result => {
+      return resolver.require(url)
+    })
+    .then(result => {
+      cb(null, result.source, url, result.provider, result.url)
+    })
+    .catch(err => {
+      err
       cb('Unable to import "' + url + '": File not found')
-    }
+    })
   }
 }