Update readme methods

[parnic]

From the original PR (I didn't read the Readme changes as closely as I should have), the top of the Readme says this:

All of the previous events are still present and should still be added to the listeners

This is not accurate (one example is that poolStatus is now equipmentState) and should be changed. I don't mind doing that after taking this PR, but wanted to mention it in case it was unintentional.

[parnic]

These notes, and the review suggestions, are for me to remember after merging the PR.

• The All Messages section needs to be updated to change the messageId property into action.
• SLAddClient, and many other message types, say they are returned with their emitted events, implying that they contain the properties and methods that "all messages" contain, but this is not the case. It is no longer possible to use the "all messages" methods and properties on any of these; they have a senderId and a "val" property, for the SLSimple*Data types, and a bunch of other unique properties in other cases.
• SLCancelDelay is crossed out but shouldn't be.
• SLChemData has an undocumented balance property.
• SLControllerStateData doesn't exist.
• SLControllerConfigData documents its properties very differently (less descriptive) than other responses.
• SLDeleteScheduleEventById no longer responds with the deleted schedule's id.
• SLGetGatewayDataMessage -> SLReceiveGatewayDataMessage
• SLReceiveGatewayDataMessage properties are not available on the message itself and must be acquired with .data or .get(). (This is inconsistent with the vast majority of the events' behaviors.)
• SLGetHistoryData -> SLHistoryData
• SLGetPumpStatus -> SLPumpStatusData
• SLPumpStatusData.pumpCircuits.pumpSetPoint -> speed
• SLScheduleData is now an array with the "events" properties directly on each element.

And I need to spend time looking over the rest.