Fix for AWS credentials when using multiple accounts in configuration

On further investigation of the issue #9 I believe there is an issue in the way BasicServer is reading the config file. It appears to always reference the base credentials rather than using the account information.

This pull request contains two separate commits. The first commit e-gineer/edda@1f788fa2eefd645c52eda8346d60fe4e2eb755a5 fixes this in the simplest possible way through use of Utils.getProperty in BasicServer. The second commit e-gineer/edda@9619afeeae9a9620bc9ba885d5886c8154462403 goes further to align the lookup of region config into the same code location.

Hopefully you can merge. Thanks.