CLI: --files parameter is unwieldy

[jimmylewis]

Functional impact

It's inconvenient to type --files for every individual file (also, why is --files pluralized if it can only specify one file?)

Minimal repro steps

1. libman install jquery@3.3.1 --files jquery.js --files jquery.min.js --files jquery.min.map

Expected result

--files ought to be the last parameter, and everything after it should be considered a file name. This proposed behavior is similar to the -- parameter in GNU convention.

The above command could be simplified to:

libman install jquery@3.3.1 --files jquery.js jquery.min.js jquery.min.map

In the following, --destination and foo would be considered file names.

libman install jquery@3.3.1 --files jquery.js jquery.min.js jquery.min.map --destination foo

Actual result

It's tedious.