message: cli flags override params and capabilities, instead of being additive
diff: @@ -135,10 +135,7 @@ if (configuration.timeout === 'undefined') configuration.timeout = undefined
  if (program.capabilities) {
  try {
  - Object.assign(
  - configuration.capabilities,
  - Capabilities.parseString(program.capabilities)
  - )
  + configuration.capabilities = Capabilities.parseString(program.capabilities)
  } catch (e) {
  winston.debug('Failed to parse inline capabilities')
  }
  @@ -146,10 +143,7 @@ if (program.capabilities) {
  if (program.params) {
  try {
  - Object.assign(
  - configuration.params,
  - Capabilities.parseString(program.params)
  - )
  + configuration.params = Capabilities.parseString(program.params)
  } catch (e) {
  winston.debug('Failed to parse additional params')
  }
  