dabba: list interface as default action

Signed-off-by: Emmanuel Roullit <emmanuel.roullit@gmail.com>
dabba: refactored CLI design for 'capture'.

Signed-off-by: Emmanuel Roullit <emmanuel.roullit@gmail.com>
dabba: refactored CLI design for 'capture settings'.

Signed-off-by: Emmanuel Roullit <emmanuel.roullit@gmail.com>
dabba: readd '--help' option.

Signed-off-by: Emmanuel Roullit <emmanuel.roullit@gmail.com>
dabba: refactored CLI design for 'capture start'.

Signed-off-by: Emmanuel Roullit <emmanuel.roullit@gmail.com>
dabba: refactored CLI design for 'capture stop'.

Signed-off-by: Emmanuel Roullit <emmanuel.roullit@gmail.com>
dabba: remove redundant code.

Signed-off-by: Emmanuel Roullit <emmanuel.roullit@gmail.com>
test: adjust unit test to fit 'capture' refactoring.

Signed-off-by: Emmanuel Roullit <emmanuel.roullit@gmail.com>