Updates README known limitations and spelling (#5)

Closes Issue #4

Author: danielpatenaude

README.md

@@ -16,7 +16,7 @@ For example: the panel underperforming (red) is partially blocked by a neighbor'
     * The Enlighten v4 API does not provide any documentation on what happens whe `refresh_token` expires (1 week validity) and how a new one is generated. The step to generate the original `access_token` and `refresh_token` in [Generate OAuth2 access_token and refresh_token](https://developer-v4.enphase.com/docs/quickstart.html#step_8) seems to only allow the route to be used a single time for an authorization code (auth_code).
     * As such, _the enlightenAPI_v4_ constructor provided in this repository will refresh the tokens using the [Generate new access_token and refresh_token using refresh_token](https://developer-v4.enphase.com/docs/quickstart.html#step_10) and update the _enlighten_v4_config.json_ to contain the new tokens. This ensures that each day when the script is run, the tokens are refreshed and kept well within the refresh_token's 1 week validity.
 2. Inverter Telemetry Reporting:
-    * It appears there's a new v4 route (/api/v4/systems/{System_id}/devices/micros/{serial_no}/telemetry) that can get microinverter data based on a date range. This seems the more ideal way to get daily inverter data than my current way of having to get the current lifetime data minus the stored value. But unfortunately I have not been able to successfully call this route using the Enlighten API v4 docs. So maybe this route doesn't do what I think it does, and their docs don't make it very clear what it does. I always get a 401 - Not Authorized. If someone is able to get that figured out, please feel free to let me know.
+    * It appears there's a new v4 route (/api/v4/systems/{System_id}/devices/micros/{serial_no}/telemetry) that can get microinverter data based on a date range. This seems the more ideal way to get daily inverter data than my current way of having to get the current lifetime data minus the stored value. Unfortunately, this route requires [paid plans and is not available using the free 'Watt' plan](https://github.com/danielpatenaude/python_enlighten_api/issues/4). For users of the free developer 'Watt' plan, you'll always receive a `401 - Not Authorized`.
 
 ## Requirements
 Requires Python 3.6.8 or later installed. Much effort has been taken to ensure this application does not require additional modules besides what is included standard with Python.
@@ -97,7 +97,7 @@ This repository contains a few scripts used to hit the Enphase Enlighten API and
 
 ### run_inverter_daily_stats.py
 
-Runs the Enlighten API route 'inverters_summary_by_envoy_or_site' to collect the lifetime energy produced by each inverter. The Enphase API lacks the granulatiry of seeing per inveter daily stats. So this script provides a means to do that. If you call this route once a day before your solar is producing power (e.g.: 4am) you get the total lifetime power produced by each inverter, including the previous day. If you track this total lifetime energy value every day, you can then subtract the current day's total from the previous day lifetime total. That gives you the daily production value for that inverter. Note: if your Envoy is connected via low bandwidth Cellular, data only refreshes to Enlighten every 6 hours. So perform this route the next day in the early morning to ensure you get complete data.
+Runs the Enlighten API route 'inverters_summary_by_envoy_or_site' to collect the lifetime energy produced by each inverter. The Enphase API lacks the granularity of seeing per inverter daily stats. So this script provides a means to do that. If you call this route once a day before your solar is producing power (e.g.: 4am) you get the total lifetime power produced by each inverter, including the previous day. If you track this total lifetime energy value every day, you can then subtract the current day's total from the previous day lifetime total. That gives you the daily production value for that inverter. Note: if your Envoy is connected via low bandwidth Cellular, data only refreshes to Enlighten every 6 hours. So perform this route the next day in the early morning to ensure you get complete data.
 
 The resulting data is stashed in a .json file. The file organizes the data by microinverter (by ID), then by day. So you can easily parse this historical data for daily production values.
 For example: