Adding custom cache optional parameter to decorators, fixing flush and other small changes.

Changing the order of RedisConnect constructor arguments (host, port, db is a more natural order).
Fixing tests and making tests to leave redis instance clean (same keys as before the tests).
Correcting hashkeys comment
Merge pull request #6 from fjsj/master

szaydel changes and decorator with cache param
More rigorous tests.

Checking for connection with redis-server on TesCase setUp method.
Testing flush considering not only the __len__ method (which uses scard), but also using redis KEYS command directly.
New version number 0.0.3.

Changing order of host, port and db in SimpleCache constructor.
Additions to README.
Merge pull request #7 from fjsj/master

New version number 0.0.3