preparing v2

[sio4]

I want to start version 2 of envy. (major version change since the important behavior will be changed)

The current behavior of envy is that it automatically loads .env file from the working directory and overwrites all pre-existing environment variables with the values from the .env. However, this behavior is far from the general priority of configuration: the command-line argument is the first priority, followed by environment variables, otherwise using the configuration file as a default.

Also, nowadays Cloud Computing and/or container technology became the standard runtime platform for applications and most of them provide environment variable-based runtime configuration with static virtual machine images or container images. So file-based configuration should be able to be overridden with environment variables.

After this, API clean-up will be followed before releasing v2.

fixes #36

[paganotoni]

Looks good to me and I like the rationale behind all this. ENV variables addition usually show more purpose than files which could be easy to forget.