Named cycle groups

[jg-rp]

When the cycle tag is given a name, Python Liquid will use that name and all other arguments to distinguish one cycle from another. Ruby Liquid will disregard all other arguments when given a name. For example.

{% cycle a: 1, 2, 3 %}
{% cycle a: "x", "y", "z" %}
{% cycle a: 1, 2, 3 %}

Ruby Liquid Output:

1
y
3

Python Liquid Output:

1
x
2

[jg-rp]

Fixed with #99 and the use of liquid.future.Environment instead of liquid.Environment.