[FEATURE REQUEST] filter files to be included

[the-liquid-metal]

Suppose that i have 2 file types .jpg and .txt in the list. Before renaming, i want to filter out all .txt. Currently, this cannot be done because both file types have the possibility of being renamed.
Suggestion: add filename filter field in the middle of window (between Files/folders section and Rules section). This field must be regex in order to accomodate any possibilities. If filename matches with the pattern, than the file will be included.