Fix a Typo in README and a ZeroDivisionError (#1)

Co-authored-by: JMallone <[email protected]>

Author: Jmallone

README.md

@@ -27,7 +27,7 @@ This script is purely for the purposes of archival use only.
 
 ```bash
 # Install the requirements. Once only.
-python -m pip install -r requirements.py
+python -m pip install -r requirements.txt
 python birdwatch.py --url www.twitter.com/<profile>
 
 # For more help use:

birdwatch.py

@@ -143,9 +143,12 @@ def _func(lst):
 def window_average(window):
     def _func(lst):
         v = lst[:-min(window, len(lst))]
+        if len(v) == 0:
+            return lst[-1]
         return sum(v) / len(v)
     return _func
 
+
 def constant(const):
     def _func(lst):
         return const