Add ability to configure tasks via command line

[carakessler]

we should allow us to specify task configurations in the command line, essentially how eslint does. Right now we can only turn a task on via command line.

eslint --rule 'quotes: [2, double]'
eslint --rule 'guard-for-in: 2' --rule 'brace-style: [2, 1tbs]'
eslint --rule 'jquery/dollar-sign: 2'

[scalvert]

Agree. FWIW eslint interally uses Levn (https://github.com/gkz/levn). We should align to this.