fix: import modules from relative folder path, improve logging (#4)

- Added possibility for the user to specify a print-all console logger.
  The user can now use `monorepoHelper(...).logger(consoleLogger)`.
- Added a new logging level: TRACE. Activate it by usinng the
  consoleLogger, or by constructing a new logger object with a proper
  `trace` field
  (e.g. `helper.logger({ ...nullLogger, consoleLogger.trace })`
- Major overhaul on the module resolution algorithm. Now, relative
  imports work! \o/

Closes #4.

package.json

@@ -61,9 +61,11 @@
   },
   "dependencies": {
     "glob": "^7.1.3",
-    "resolve": "^1.8.1"
+    "resolve": "^1.8.1",
+    "chalk": "^2.2.0"
   },
   "devDependencies": {
+    "@types/chalk": "^2.2.0",
     "@types/glob": "^7.1.1",
     "@types/node": "^10.12.10",
     "@types/resolve": "0.0.8",