add support for touch command
Allow specifying an empty server list.

If the server list is empty, behave the same as if all servers are down.
This allows clients to not care whether memcache is actually in use:

mc = memcache.Client(get_my_memcache_servers())
mc.get('cache')

If you're not using memcache at all, get_my_memcache_servers() just
returns [], and the client code doesn't need to know the difference.
Previously, it would fail:

>>> mc = memcache.Client([])
>>> mc.get('x')
  File "memcache.py", line 353, in _get_server
    server = self.buckets[serverhash % len(self.buckets)]
ZeroDivisionError: integer division or modulo by zero
Merge pull request #29 from zewt/allow-empty-server-list

Allow specifying an empty server list.
Changelog entry for zewt patch.
Merge pull request #28 from erankor/master

add support for touch command
Adding Changelog for touch()
tests/test_setmulti.py: Remove `unittest.main()`
Add .travis.yml for Travis CI
README.md: Add Travis CI build badge
Merge pull request #33 from msabramo/travis

Add support for Travis CI
Wrapping the unit-test main in if __name__.
a Please enter the commit message for your changes. Lines starting
Re-flowing README.
Merge branch 'py33_fixes' of https://github.com/cabrera/python-memcached into cabrera-py33_fixes

Conflicts:
	README.md
	memcache.py
	tests/test_setmulti.py
Removing debug print that slipped in.
Fix an `except` for Py3

It appears to have been introduced with the merge of PR #28 and I guess
PR #26 was created before this and didn't handle it.
Sneak in a few PEP8 fixes
Merge pull request #1 from msabramo/cabrera-py33_fixes_tweak_except

Cabrera py33 fixes tweak except