Please review options handling

[mgoritzk]

This tool is great but a start with this tool would be much, much more easier, if the options handling would work basically the same.

Sometimes options works with only one "-" character, sometimes it is necessary to use two "-" characters. Sometimes the equal character is needed, sometimes not. Passing an option via command line is sometimes different than in the config file (e.g. upstream vs upstreams).

I am sure that unifying options handling and names will increase attention for this product enormously.

[ploxiln]

All command-line flags accept both one - and two --. All command-line flags work with an = or with a space before the value. This is the behavior of the go standard-library "flag" package. Any inconsistency is just in the documented examples.

Pluralization differences are intentional and meaningful, but there are a couple unintentional inconsistencies. See #363