Add additional resource code guidelines

[jlillis]

I've added a few proposed guidlines for resources code:

1. Using error for error handling
2. Avoiding anonymous functions
3. Use of constants/avoiding magic numbers
4. Basic naming conventions
5. Avoid OOP
6. Use range-based for loops

Most of these are pretty standard practice already, while others (particularly 1 and 3) are personal practices of mine that I think are worth considering.

Resolved

[Lpsd]

Thanks for the contribution!