Describe the bug
$field->slug() (and its underlying Str::slug() usage) doesn't take into account custom slug rules that may have been set up for a language.

To Reproduce
Steps to reproduce the behavior:

1. Set up language-specific slugs
2. Use $field->slug() on something

Expected behavior
I would definitely

Add optional buttons for all headings h1 to h6

Also: Don't use H character for headings in button label because it only makes sense for english speakers.

Use 'A' character instead:

 <button>A<sup>1</sup><button>

Output would look like this:

![screen shot 2016-04-19 at 8 16 42 pm](https://cloud.githubusercontent.com/assets/1783777/14661593/16fcdfe4-066c-11e6-

When you choose to import content and select a file which contains no markdown or raw text, you get this error:

mb_eregi_replace() expects parameter 3 to be string, null given

A better error handling should be added to hint the user to choose a compatible file type.

Is there an easy way to add a custom field to an order like a note from the buyer to the seller? That would be a great functionality... E.g. where personal details like name and address are filled in to show on possible fields. Did not find a solution in docs so before enhancing the templates want to ask if there is sth integrated already

readme.md instructs to go to site/plugins and then use git clone. This results in module being cloned into /site/plugins/site/plugins .

As in the Kirby structure field, the dynamic width feature would be very useful.

https://getkirby.com/docs/reference/panel/fields/structure#table-columns

columns: 
  title: 
    width: 3/5      
  images: 
    width: 1/5
  price: 
    width: 1/10