Command line interface

[ceholden]

Move from many command line programs that use docopt for CLI parsing to one centralized yatsm CLI using click.

Motivation:
There are a lot of CLI scripts already that process data, make maps, or perform housekeeping. The map scripts are prefixed with the name "yatsm_" but none of the others are. If we had one centralized yatsm command then it would be easier to navigate the various scripts.

Example:

$ yatsm --help
YATSM algorithm text

Options:
--verbose
--help

Commands:
lines         runs lines
cache         housekeeping for cache data
changemap     makes changemaps
map           makes maps

[ceholden]

CLI is now implemented using click. Still TODO:

1. Update and add to CLI tests
2. Script documentation
3. Installation instructions updates