Log Message:
Update py-flask-admin to 1.0.8.

1.0.8
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Highlights:

* Cleaned up documentation, many thanks to Petrus Janse van Rensburg.
* More flexible menu system, ability to add links to menus
* Human-readable filter URLs
* Callable filter `options`
* `EmailField` filter
* Simple accessibility fixes
* `InlineFormField` now accepts `widget_args` and `form_rules` arguments
* Support for newer wtforms versions
* `form_rules` property that affects both create and edit forms
* Lots of bugfixes