added a note for implications regarding the reversion to original mqt…

…t.js typings.

README.md

@@ -3,6 +3,9 @@
 This library isn't just a wrapper around MQTT.js for angular >= 2.
 It uses observables and takes care of subscription handling and message routing.
 
+For reasons of convenience, I removed the copied typings from mqtt.js and added it as a dev-dependency while still bundling the browserified latest version of it.
+This means although you have the possibility to use `mqtt`, `mqtts`, `tcp`, `ssl`, `wx` or `wxs` as the protocol in the client options, you can't, because this is a browser library where you can't conntect with something other than websockets. You also can't use `key`, `cert` and `ca` for the same reasons.
+
 If you have any issues using this library, please visit it's [homepage](https://sclausen.github.io/ngx-mqtt/) and look for similar issues in the issue tracker before you file a bug.
 
 ## **ngx-mqtt >= 6 is only compatible with angular >= 6**