rpc: add capture stop all rpc call.

Signed-off-by: Emmanuel Roullit <emmanuel.roullit@gmail.com>
dabbad: add capture stop all rpc function.

Signed-off-by: Emmanuel Roullit <emmanuel.roullit@gmail.com>
dabba: add capture stop all command in cli.

Signed-off-by: Emmanuel Roullit <emmanuel.roullit@gmail.com>
test: use stop-all command in tests.

Signed-off-by: Emmanuel Roullit <emmanuel.roullit@gmail.com>
Merge pull request #8 from eroullit/capture-stop-all

Add command to stop all running captures