fix mapnik version

[hyperknot]

This PR does the following things:

1. Unifies the npm install and package.json installed modules into a single package.json one.
2. Updates the non-critical (above the blank line) libraries to 1.x syntax instead of the ^1.2.3 syntax (just for better readability).
3. Specifies all the critical libraries to an exact patch version (below the blank line).

Built, tested and works fine.