Fix Codacy issues - Code Style, Error Prone, etc

Codacy Dashboard for vrpRouting: https://app.codacy.com/gh/pgRouting/vrprouting/dashboard

Related PRs made for pgRouting:
- https://github.com/pgRouting/pgrouting/pull/2183
- https://github.com/pgRouting/pgrouting/pull/2184
- https://github.com/pgRouting/pgrouting/pull/2185
- https://github.com/pgRouting/pgrouting/pull/2186