no more global session

Signed-off-by: Kenneth Reitz <me@kennethreitz.org>

README.rst

@@ -25,7 +25,9 @@ Make a GET request to 'python.org', using Requests:
 
 .. code-block:: pycon
 
-    >>> from requests_html import session
+    >>> import requests_html
+    >>> session = requests_html.Session()
+
     >>> r = session.get('https://python.org/')
 
 Grab a list of all links on the page, as–is (anchors excluded):
@@ -73,14 +75,14 @@ Select Elements within Elements:
 
     >>> about.find('a')
     [<Element 'a' href='/about/' title='' class=''>, <Element 'a' href='/about/apps/' title=''>, <Element 'a' href='/about/quotes/' title=''>, <Element 'a' href='/about/gettingstarted/' title=''>, <Element 'a' href='/about/help/' title=''>, <Element 'a' href='http://brochure.getpython.info/' title=''>]
-    
+
 Search for links within an element:
 
 .. code-block:: pycon
 
     >>> about.absolute_links
     {'http://brochure.getpython.info/', 'https://www.python.org/about/gettingstarted/', 'https://www.python.org/about/', 'https://www.python.org/about/quotes/', 'https://www.python.org/about/help/', 'https://www.python.org/about/apps/'}
-    
+
 
 Search for text on the page:
 

requests_html.py

@@ -202,5 +202,3 @@ class Session(requests.Session):
 
         response.html = HTML(response=response)
         return response
-
-session = Session()