Insert a user defined string in a user defined position. The string may contain
formatting parameters.
"At position": position to insert string at. Set value of 1 to insert at
the beginning. If the value exceed filename's length, string will be inserted
at the end of the filename.
"Start from": counting direction for the position defined.
"Overwrite": inserted string will overwrite existing characters.
Example
Insert the string "_-" at position 3 from beginning of filename. Overwrite is
unchecked.
01_Mercury_Rave_-_Holes.mp3 >>>
01_-_Mercury_Rave_-_Holes.mp3