Rename docs to "Particle filters for Python"

Since pypfilt implements several particle filters, it is misleading for
the documentation title to refer only to the bootstrap particle filter.

doc/conf.py

@@ -259,7 +259,7 @@ texinfo_documents = [
         'pypfilt documentation',
         'Rob Moss',
         'pypfilt',
-        'Bootstrap particle filter for epidemic forecasting.',
+        'Particle filters for Python.',
         'Miscellaneous',
     ),
 ]

doc/index.rst

-Bootstrap particle filter for Python
-====================================
+Particle filters for Python
+===========================
 
 Welcome to the pypfilt_ documentation.
 This package implements several particle filter methods that can be used for recursive Bayesian estimation and forecasting.