Use recursive array merging for getDefaultConfig() in loadConfigFile()
Recursively merge 'config.yml' and 'config_local.yml' too
Use array_merge_recursive_distinct() in place of array_merge_recursive()
for config file merges
Merge pull request #1786 from GawainLynch/hotfix/getDefaultConfig-array-merge

Use recursive array merging for getDefaultConfig() in loadConfigFile()