Adds support for setting environment via regexp files

• regexp_nodes now emits a top level 'environment: production' setting for a client, unless a more-specific environment is set in the environment/ subdirectory.

• added better documentation text including a caveats section on some perhaps-not-obvious implications of multiple matches for parameters and environment.

• cleaned up code smell stuff to remove comments at block 'end' statements that described what block that was. i need to either get a better ide or refactor so it's obvious...