fix version command so that it will work with all supported config

formats and added tests.

This resolves #609,  #634, and #657.

The issues ping-pong between map[string]interface{} and map[interface{}interface{}. This is due to the differences between the way TOML and YAML `param` settings are stored. JSON is also affected, but I am not sure which way panics JSON as I did not test JSON configs before implementing fix/tests.

`getDateFormat()` now checks the interface type and converts `map[interface{}]interface{})` to `map[string]interface{}`.

Tests were added, which I should have done in the first place; mea culpa