docs: Fix a few typos

There are small typos in:
- experiments/ILS.py
- experiments/gauss.py
- experiments/ukf_range.py
- kf_book/book_plots.py

Fixes:
- Should read `standard` rather than `standand`.
- Should read `search` rather than `seach`.
- Should read `object` rather than `obect`.
- Should read `measurement` rather than `measurment`.
- Should read `consistent` rather than `consistant`.

experiments/gauss.py

@@ -48,7 +48,7 @@ class gaussian(object):
         return (self.mean, self.variance)
 
     def __getitem__ (self,index):
-        """ maybe silly, allows you to access obect as a tuple:
+        """ maybe silly, allows you to access object as a tuple:
         a = gaussian(3,4)
         print (tuple(a))
         """