Switch to ES6 modules, change test behavior

Now project is using ES6 modules and displays coverage reports for
browser tests (made via karma), while nodejs tests only keygens.

src/keygen/insyde.ts

@@ -2,10 +2,8 @@
 /* tslint:disable:no-var-requires */
 /* Maybe need fixing for browsers where numbers is 32-bits */
 /* Some Acer, HP  laptops. 8 digit */
-import type JSBIT from "jsbi";
+import JSBI from "jsbi";
 import { makeSolver } from "./utils";
-const JSBI = require("jsbi");
-type JSBI = JSBIT;
 
 export class Crc64 {
     private static tableCache: {[key: string]: JSBI[]} = {};

src/keygen/sony_4x4.spec.ts

@@ -1,5 +1,5 @@
 /* tslint:disable:no-var-requires */
-const JSBI = require("jsbi");
+import JSBI from "jsbi";
 import { modularPow, sony4x4Keygen, sony4x4Solver } from "./sony_4x4";
 
 describe("Sony 4x4 BIOS Keygen", () => {

src/keygen/sony_4x4.ts

@@ -1,9 +1,7 @@
 // based on dogbert's pwgen-sony-4x4.py
 /* tslint:disable:no-bitwise */
 /* tslint:disable:no-var-requires */
-import type JSBIT from "jsbi";
-const JSBI = require("jsbi");
-type JSBI = JSBIT;
+import JSBI from "jsbi";
 import { makeSolver } from "./utils";
 
 const otpChars: string = "9DPK7V2F3RT6HX8J";