remove outdated note about epoll from readme, add note about installi…

…ng on non-linux systems

README.md

@@ -46,6 +46,9 @@ can now return Promises in scenarios where undefined was previously returned.
 npm install onoff
 ```
 
+Note that although it's possible to install onoff on non-Linux systems the
+functionality offered by onoff is only available on Linux systems.
+
 ## Usage
 
 #### LEDs and Buttons
@@ -456,12 +459,6 @@ The GPIO sysfs interface can also be used for interrupt detection. onoff can
 detect several thousand interrupts per second on both the BeagleBone and the
 Raspberry Pi.
 
-Note that the [epoll package](https://github.com/fivdi/epoll) is currently
-only supported on Linux. Attempting to use onoff on non-Linux systems will
-result in runtime errors similar to:
-
-`Error: Module did not self-register.`
-
 
 ## Configuring Pullup and Pulldown Resistors