Clean up npm package (#904)

* ignore everything but official contracts for npm

* add tests to npm package

* remove truffle migrations stuff

* remove seemingly unused npm dependency

* clean up dependencies

Author: frangio

contracts/.npmignore

@@ -0,0 +1,2 @@
+mocks
+examples

contracts/lifecycle/Migrations.sol

@@ -2,6 +2,10 @@
   "name": "zeppelin-solidity",
   "version": "1.8.0",
   "description": "Secure Smart Contract library for Solidity",
+  "files": [
+    "contracts",
+    "test"
+  ],
   "scripts": {
     "test": "scripts/test.sh",
     "lint": "eslint .",
@@ -42,6 +46,7 @@
     "chai-as-promised": "^7.0.0",
     "chai-bignumber": "^2.0.0",
     "coveralls": "^2.13.1",
+    "dotenv": "^4.0.0",
     "eslint": "^4.11.0",
     "eslint-config-standard": "^10.2.1",
     "eslint-plugin-import": "^2.8.0",
@@ -51,13 +56,9 @@
     "ethereumjs-util": "^5.1.2",
     "ethjs-abi": "^0.2.1",
     "ganache-cli": "6.1.0",
-    "mocha-lcov-reporter": "^1.3.0",
     "solidity-coverage": "^0.4.15",
     "solium": "^1.1.6",
     "truffle": "^4.1.5",
     "truffle-hdwallet-provider": "0.0.3"
-  },
-  "dependencies": {
-    "dotenv": "^4.0.0"
   }
 }