Add tests for testnet headers (#20)

* add test section for adding testnet headers

* add testnet tests

* update dark gravity wave

* reactivate mainnet headers

* reactivate mainnet headers

* update dark-gravity-wave

* bump version

* update package lock

* remove bn.js from deps

* bump patch version

* update eslint-plugin-import dep

* update package lock

* revert superfluous bump

* update package lock

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@dashevo/dash-spv",
-  "version": "1.1.2",
+  "version": "1.1.3",
   "description": "Temporary repo until spv functions moved into dashcore-lib",
   "main": "index.js",
   "scripts": {
@@ -11,17 +11,16 @@
   "author": "",
   "license": "MIT",
   "dependencies": {
-    "@dashevo/dark-gravity-wave": "^1.1.0",
+    "@dashevo/dark-gravity-wave": "^1.1.1",
     "@dashevo/dashcore-lib": "^0.17.4",
     "@dashevo/dash-util": "^2.0.3",
-    "bn.js": "^4.11.8",
     "levelup": "^4.0.1",
     "memdown": "^3.0.0"
   },
   "devDependencies": {
     "eslint": "^5.16.0",
     "eslint-config-airbnb-base": "^13.1.0",
-    "eslint-plugin-import": "^2.17.2",
+    "eslint-plugin-import": "^2.17.3",
     "mocha": "^5.2.0",
     "should": "^13.2.3"
   }