Add support for config file and minimum and maximum values in docs

Allows you to supply a config file via `prmd -s prmd-config.json` and override any of the other settings you would supply. This also supports YAML config files.

Couple of extra bonus things:
* Remove the url style parameter from the command line and only supply it via the config file.
* Add support for `minimum` and `maximum` parameters to be displayed in the docs
* Little bug fix 
How about this format as a proposal:

Name | Type | Description | Example |
------| ---- | ------------- | ----------|
__awesomeness__ | _integer_ | Value of awesomeness allocated<br> __Minimum:__ `1` _(exclusive)_<br> __Maximum:__ `250` _(exclusive)_ | `35`
__awesomeness__ | _integer_ | Value of awesomeness allocated<br> __Minimum:__ `1`<br> __Maximum:__ `250` (exclusive) | `35`
__awesomeness__ | _integer_ | Value of awesomeness allocated<br> __Minimum:__ `1` (exclusive) | `35`
__awesomeness__ | _integer_ | Value of awesomeness allocated<br>  __Maximum:__ `250` (exclusive) | `35`