Run CSScomb does nothing on an unsaved tab (file_name() is None) #101

Claude reports: running "Run CSScomb" on an unsaved tab does nothing.

get_syntax() accepts an unsaved plain-text buffer (is_unsaved_buffer_without_syntax), but comb() then calls os.path.dirname(self.view.file_name()). For an unsaved view file_name() is None, so this raises and nothing is combed.

Steps (Sublime Text build 4200, package 2017.10.06, Windows):

1. New tab (File > New File), plain text.
2. Type a{color:#FFF;margin:0px}.
3. Run CSScomb.

Result: the text is unchanged. The same text saved as a.css is combed correctly.

Suggested fix: use folder = os.path.dirname(self.view.file_name() or '') (or skip the folder argument when there is no file). The same applies to is_scss(), which calls self.view.file_name().endswith('.scss') on None when the scope is not CSS.

Related: #54 (same kind of None problem, closed), #23.