Enable eslint import checks and fixed the reported errors (#878)

Summary:
Pull Request resolved: https://github.com/facebook/flipper/pull/878

1) Enabled eslint error reporting for unresolved imports and fixed all the errors
2) Enabled eslint for typings (d.ts) and fixed all the errors

Reviewed By: passy

Differential Revision: D20335151

fbshipit-source-id: 7b142281a406b32df0f02a5cd0d7d05eba941acd

desktop/types/line-replace.d.ts

@@ -8,11 +8,16 @@
  */
 
 declare module 'line-replace' {
-    export default function(args: {
-        file: string; 
-        line: number; 
-        text: string; 
-        addNewLine: boolean; 
-        callback: (args: {file: string; line: number; replacedText: string; text: string}) => void;
-    }): void;
+  export default function(args: {
+    file: string;
+    line: number;
+    text: string;
+    addNewLine: boolean;
+    callback: (args: {
+      file: string;
+      line: number;
+      replacedText: string;
+      text: string;
+    }) => void;
+  }): void;
 }