Filter treeview with list only asciidoc files.

[rajmahendra]

In the left side column treeview it display all files and folders.
Though AsciidocFX supports only asciidoc files its good to filter only asciidoc extension files.

This will reduce the big list of unwanted files.

[rahmanusta]

Thats good point Raj, we can imrove directory listview as you say.

[rahmanusta]

It is only listing images and asciidoc files now.