Added a menu option to add 'new' files to tagger

A file is considered 'new' if it has been modified in the last five hours. This setting can be stored in the config later. Only the starting directory is scanned for new files currently. A context menu option can be added to the treeview to add new files from a folder.

Yes and no ;)

I would do, but untested:

```python
            combo_ops = OrderedDict([
                (N_(u"Anytime"), time.time()),
                (N_(u"In the last hour"), 1*60*60),
                (N_(u"In the last 5 hours"), 5*60*60),
                (N_(u"In the last 10 hours"), 10*60*60),
                (N_(u"In the last 24 hours"), 24*60*6)
            ])
            for op in combo_ops.keys():
                combo.addItem(_(op))
            file_dialog.layout().addWidget(QtGui.QLabel(_(u"Files created:")))
```
`N_()` is used to mark a string for translation (but it does nothing else)
`_()` will return translated string corresponding to passed one, if possible, or the string itself if no translation is available.

Also (unrelated), you don't need to add ';' at end of line, even if python doesn't complain, it is useless here.