Don't add sentence spacing if submission is empty

When you retry, it actually sends an empty submission, so if you have
add sentence spacing on, retrying could add an extra action with a
single space.

(cherry picked from commit 151407a001)

utils.py

@@ -91,6 +91,9 @@ def removespecialchars(txt, vars=None):
 # If the next action follows a sentence closure, add a space
 #==================================================================#
 def addsentencespacing(txt, vars):
+    # Don't add sentence spacing if submission is empty or starts with whitespace
+    if(len(txt) == 0 or len(txt) != len(txt.lstrip())):
+        return txt
     # Get last character of last action
     if(len(vars.actions) > 0):
         if(len(vars.actions[vars.actions.get_last_key()]) > 0):