make `ee._maxListeners` public

[jonathanong]

any reason it's private? i'd like to increment/decrement the value as i add/remove listeners to avoid the stupid warning while not being irresponsible. specifically:

ee.maxListeners++

ee.once('event', function () {
  // do stuff
  ee.maxListeners--
})

[indutny]

Can't you just do it with a setMaxListeners?

[dougwilson]

Can't you just do it with a setMaxListeners?

The idea is to ++ and --; setMaxListeners would work, if there was a way to get the current max listeners in a public API.

[indutny]

Ok, sou you really need getMaxListeners, this sounds reasonable! Would you please mind opening a PR for this?

[vkurchatkin]

@indutny maybe just rename _maxListeners -> maxListeners? getMaxListeners looks too java-ish (=ugly)

[trevnorris]

@vkurchatkin I wouldn't say it's java-ish. Now retrieveTheValueForMaxListeners() would be java-ish. ;-P

Anyway, I prefer this because internal implementation can change in the future and changes in the implementation details can be masked behind the function call.