allow parameters / options in default action

[butonic]

this allows me to use https://github.com/markwu/todo-cli-plugins/blob/master/view and set is as the default action with export TODOTXT_DEFAULT_ACTION="view context"

[inkarkat]

Needs tests and documentation.

[karbassi]

@butonic could you write tests for this?

[butonic]

I moved to another tool. But you can edit this branch or close the PR.

[chrysle]

I would write some tests and docs, but can't edit this.

[inkarkat]

I would write some tests and docs, but can't edit this.

Just create your own branch (off butonic's master branch), and submit a separate PR.