Migration to truffle 5 (and web3 1.0 (and BN)) (#1601)

* Now compiling using truffle 5.

* Migrated some test files, missing BN scientific notation usage.

* Now using BN time values.

* Migrate ERC20 tests.

* Migrate all ERC20 tests.

* Migrate utils, payment and ownership tests.

* All tests save ERC721 migrated.

* Migrated ERC721 tests.

* Fix lint errors.

* Delete old test helpers.

* Fix remaining crowdsale tests.

* Fix signature bouncer tests.

* Update how constants is used.

* Compile script pre-removes the build dir.

* Fix SafeMath tests.

* Revert "Compile script pre-removes the build dir."

This reverts commit 247e745113.

* Fix linter errors.

* Upgrade openzeppelin-test-helpers dependency.

* Update openzeppelin-test-helpers dependency.

* Define math constants globally.

* Remove unnecessary ether unit.

* Roll back reduced ether amounts in tests.

* Remove unnecessary toNumber conversions.

* Delete compile script.

* Fixed failing test.

package.json

@@ -9,7 +9,7 @@
   ],
   "scripts": {
     "build": "scripts/build.sh",
-    "compile": "scripts/compile.sh",
+    "compile": "truffle compile",
     "console": "truffle console",
     "coverage": "scripts/coverage.sh",
     "lint": "npm run lint:js && npm run lint:sol",
@@ -41,7 +41,6 @@
   "homepage": "https://github.com/OpenZeppelin/zeppelin-solidity",
   "devDependencies": {
     "chai": "^4.1.2",
-    "chai-bignumber": "^2.0.2",
     "coveralls": "^3.0.1",
     "eslint": "^4.19.1",
     "eslint-config-standard": "^10.2.1",
@@ -53,11 +52,11 @@
     "ethereumjs-util": "^6.0.0",
     "ethjs-abi": "^0.2.1",
     "ganache-cli": "6.1.8",
+    "openzeppelin-test-helpers": "^0.1.1",
     "pify": "^4.0.1",
     "solhint": "^1.5.0",
     "solidity-coverage": "^0.5.4",
-    "truffle": "^4.1.13",
-    "web3-utils": "^1.0.0-beta.34"
+    "truffle": "^5.0.0"
   },
   "dependencies": {}
 }