Counter-intuitive UI on adding a new filter

Issue Summary

Some quick fixes to make things more friendly:

1. Under /admin/settings/customfilter, if the table is empty, add a link to create a new filter (e.g. "There are currently no . . . Create a new filter.")

2. When filter is created, redirect to admin/settings/customfilter/%filter . There's no sense in creating a new filter without giving it rules, and the extra click from the list table is annoying.

3. Under/admin/settings/customfilter/%filter, if there are no rules, add a link to create a new rule (same as 1, but for rules under a filter).

4. In the filter list in /admin/settings/customfilter, change the rule name to non-link, and add an "edit rules" link under the action column. Editing rules is an action, and I was expecting to see it there. Name should be only a label.

5. In the rules list in /admin/settings/customfilter/%filter, change the "add" link to "add sub-rule", since a simple "add" doesn't make much sense there. Also, why write a rule description if it's not displayed in this table? Where else would it be used?

6. I found the sub-rule help texts to be less than clear. A general (not per-field) explanation at the top of the page would come in useful.

That's everything that pops to mind at the moment. Nice module, thanks!