Add support for field variables in custom text settings to allow displaying media info along with custom text

[archiconda1976]

Consider adding variable parsing to the custom text entry field. This will allow customizing the display. Use case I was thinking of was displaying the current series name on one line, with a single line break tag and then the episode name on a secondary line. Currently selecting the episode in advanced option will show the episode name, but the cover art will be a screen shot from the episode vs the series or season art. Would also be nice to have a sperate custom field for TV shows vs Movies.