Fix opening in binary mode destroys parsing with python 3 (#25)

Fix performance graph can't read log with Python 3

octoprint_klipper/modules/KlipperLogAnalyzer.py

@@ -43,7 +43,7 @@ class KlipperLogAnalyzer():
       out = []
 
       try:
-         f = open(logname, 'rb')
+         f = open(logname, 'r')
 
          for line in f:
             parts = line.split()