Add watched checkmark to Movies, Collections, TV Shows, Season list. Remove API generated checkmark

[photonconvergence]

Adds watched checkmark to most library views.
Aligns unwatched episode count rectangle in Season list view.
Removes the last API generated watched checkmark (Season list view)

Fixes:
#312
#402
#1027

Inspired by:
#922
#1223

[1hitsong]

These changes look good to me.

[chibiconsulting]

There should be a user configuration setting to control the color & visibility of the new feature.

Having the ability to select the color of the unwatched counter and the color and/or visibility of the watched checkbox would be a great user experience improvement. With the current implementation, the library views are just a sea of blue boxes.

New settings should be in: Settings / User Interface / Libraries / General

Although could also be in: Settings / User Interface / Libraries / TV Shows as there is already a setting there to "Disable Unwatched Episodes" there; however, this should be a more global solution.

In either case, the settings would be .. / Unwatched Overlay and .. / Watched Overlay with the options being various colors or no display.