Merge branch 'rework-commands-system' into work-on-hmget-hmset

Conflicts:
	limpyd/fields.py
Move redis_connect to database module (fix #49 issue)

`import redis` in the __init__.py file make the setup.py not
loadable without redis lib already installed.
Merge pull request #43 from twidi/rework-commands-system

Rework commands system
Merge branch 'rework-commands-system' into work-on-hmget-hmset

Conflicts:
	limpyd/fields.py
	limpyd/utils.py
Move TEST_CONNECTION_SETTINGS to tests/base.py
Revert "hgmet & hmset can know accept args as in redis-py"

This reverts commit 912d4b1cda1a9aeaa1fb619d0e8387e4e959d8a3.

Conflicts:

	tests/model.py
Revert "Update doc about arguments for hmget and hmset"

This reverts commit 0e2f430d04412c1d8cabe58b4798f51d1974cbb9.
Make "redis_connect" a method of Database
ExtendedCollection filter can now accept an instance

In the ExtendedCollection, the _add_filter method (used when creating a
collection) can accept a SingleValueField in addition to a real value.

With this commit, we can now pass a RedisModel too, to use it's primary
key as the filter's value.
Failing tests to show errors in using fields as filter values
Correct passing fields and models as filter value

Before this commit, the name part of the filter wasn't used !
Merge pull request #51 from yohanboniface/move_redis_connect

Move redis_connect to database module (fix #49 issue)
Merge pull request #52 from twidi/work-on-hmget-hmset

Work on hmget hmset
Merge branch 'master' into enhance-collections

Conflicts:
	limpyd/fields.py
	limpyd/model.py
	limpyd/utils.py