Add neo-scan-api to CLI

[revett]

Feature

The neo-scan-api is not started by the CLI - fix this issue by adding it.

See the following for an example:

• https://github.com/CityOfZion/neo-local/blob/master/cli/stack/postgres.go
• https://github.com/CityOfZion/neo-local/blob/master/cli/commands/start.go