pelican-bootstrap3: cc-license.html lack of a parameter and a wrong parameter name

[izheye]

The macro cc_license_mark has two problems:

1. lack of a parameter of show_icon
2. wrong parameter name of br_after_icon

so,
firstly, add a parameter named show_icon at the head:

{% macro cc_license_mark(cc_name,
                         derivatives, commercial,
                         show_icon=false,
                         br_after_icon=false,
                         attr_markup=false,
                         attr_props={}) %}

secondly, correct the parameter name to br_after_icon at line 58 at the macro body:
{% if br_after_icon %}<br/>{% endif %}