Inherit file/folder_exclude_patterns from global settings

[laggingreflex]

Exclude file|folder_exclude_patterns

If dired_show_excluded_files is set to false, it hides files and folders that match against folder_exclude_patterns and file_exclude_patterns patterns defined in the global settings.

fixes #82

[vovkkk]

Thanks for effort

Please rename setting to dired_use_global_exclude_patterns

The checks should be probably moved to is_hidden method because prepare_filelist is not used in traverse_tree method of Refresh class; alternatively, we could change traverse_tree, but it would be probably harder to do.

Instead of if use_exclude_patterns == None or use_exclude_patterns == True and ...
use if use_exclude_patterns and ...

[vovkkk]

Yea, you see the problem is that mixes folders and files which is wrong because folder pattern may match files which are not supposed to be excluded and vice versa.
So then we have to check if name isdir twice, which seems lame.
I dunno, maybe add new method which would check if hidden and add os.sep for folders then call this method instead of items = [name for name in os.listdir(path) if not self.is_hidden(name, path)] in appropriate places;
that way we would check for isdir once and call is_hidden with additional argument isdir=True/False.
What your thoughts are?

Also, the check for attribute on Windows must be the last one, because it is the heaviest so we should not execute it if name was already defined as hidden by other check.

[laggingreflex]

These methods now return the directory list.
They are the only ones now that do isdir check so no other methods need to.