FEATURE REQUEST: Add a way to skip dependencies/prerequisites

[wvwatson]

Problem:

Sometimes there are prerequisites/dependencies that are known to have already been run in an environment before executing a sam.cr task. This could be a long running task that the user may want to avoid while re-running or debugging a top-level task.

Suggestion:

Have a way to skip dependencies like so:
./my-sam-task-binary <my-sam-task-with-dependencies> ~<dependency-to-be-skipped>

See also:

Make has functionality to skip dependencies e.g. make -o <name of dependency>