examples/sprite_sheets: Re-enable faces test & general clean up
examples/sprite_sheets: Re-enable faces test & general clean up

	General clean up:
* Comment out un-used var RESOURCE_SPRITE_SHEET
* Make OUTPUT_SHEET_FILENAME an array variable for both faces & cursors
tests.
* Use a for loop for our tests.

i8degrees/nomlib,i8degrees/nomlib,i8degrees/nomlib,i8degrees/nomlib