Improve the tree structures

[CamiAndrei]

Better highlight the files that are in sub folders.

Change the rendering of trees to quickly identify empty folders or to differentiate empty folders from folders containing files or folders.

E.g. Use Font Awesome instead for Silk Icon Theme.

[mflorea]

@CamiAndrei what exactly do you mean by:

Better highlight the files that are in sub folders.

The files are not listed in the tree, and so it doesn't seem related to this issue's title.

[CamiAndrei]

What I meant is to improve the display of the files that are in sub folders.
One example would be to be similar with what Adobe is using :

[mflorea]

I'm sorry but it's still not clear to me. To be precise, this part is clear:

Change the rendering of trees to quickly identify empty folders or to differentiate empty folders from folders containing files or folders.

But this part is not:

Better highlight the files that are in sub folders.

Where are "the files that are in sub folders" currently displayed? They're not displayed in the tree (the tree displays only folders ATM) and neither in the live table (the live table displays only the files that are directly under the folder selected in the tree AFAIK). So I don't understand how I can highlight better something that is not shown at all.