Breaking change: Remove the `expandtemplates` and `diffto` parameters
from the `Site.revisions()` method as these were deprecated in MediaWiki
1.30 and removed in 1.32.

The rvexpandtemplates parameter has been removed, but we can use
action=expandtemplates instead.

somtimes -> sometimes
if do -> if you do

Storing the message in args[0] seems more Pythonic.

While OAuthAuthorizationError inherited LoginError, they did not really share the same interface as they didn't receive the same args.

- Make `AssertUserFailedError` inherit `MwClientError` rather than `LoginError`, since it doesn't have the same args.
- Move message into args[0], which is more standard Python.

This is what is imported at the beginning of the examples.
This could also be done by changing the import to 'import mwclient'
rather than 'from mwclient import Site'.

Neither seems more correct but I have tried to follow
what seems most intended.

>>> from mwclient import Site
>>> site = mwclient.Site('en.wikipedia.org')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'mwclient' is not defined

vs.

>>> site = Site('en.wikipedia.org')
>>> page = site.pages['Greater guinea pig']
>>> text = page.text()
>>> page.exists
True

Use chunked file uploading for files larger than 1 MB as long as we’re on MediaWiki >= 1.20.

Python 3.3 is EOL, and is failing on Travis.

This fixes tests not being added to the source package.