Add config file, improve indentation and code style

[morganchristiansson]

• Consistent indentation so that code lines up correctly on github.
• Make if and for blocks use consistent style by starting them on a single line , e.g. if expr ; then.
• mkdir -p only fails if the directory cannot be created so no error handling is needed.
• prefer echo over printf
• Move credentials, urls and paths to config.sh and include it from importer.sh and exporter.sh
• Add quotes around "$KEY". If the variable is missing the path was being used as key instead and path was not provided.

Add ?w=1 to pull request URL to hide whitespace changes.