Does not run with Array config

[statianzo]

When running webpack --watch with a config like the following

module.exports = [
{
name: 'one'
//...
},
{
name: 'two'
//...
}
]

The watch flag isn't passed to the individual compilers, so the plugin's test of compiler.options.watch is insufficient. Maybe hooking into watch-run for starting is the best event to start the server for this scenario.

Also, make sure that multiple live reload servers don't get started if the plugin is included multiple times on the same port.