Filters in the URL should override filters defined when creating the view

[vitorbaptista]

For example, if I create a view with filters:

• region = ["Pakistan", "Punjaab"]
• year = [2012]

Then I add ?filters=region:Bagh in the URL, then the filters should become:

• region = ["Bagh"]
• year = [2012]

i.e. only override the field that I add something for

[vitorbaptista]

Fixed by https://github.com/ckan/ckanext-basiccharts/commit/62fdcac947fa6aba9214a45ec7424e72a6993fb9