Add Style#setGlyphs method

[anandthakker]

Follows on to #3621: add setGlyphs and setSprite methods so that smart setStyle does not have to bail out and recreate the whole style when these properties change.

update: See also #2058

[lucaswoj]

👍 Thanks for opening this ticket @anandthakker.

There are several open tickets about sprite enhancements. I'm going to think carefully about the interplay between them and whether or not any could be merged as duplicates of eachother

• Allow styles to use multiple sprites and individual images Allow styles to use multiple sprites and individual images #358
• Add Map#{add,remove}Image Add Map#{add,remove}Image #2059
• Treat "images" as nested collection of a style, like sources or layers Treat "images" as nested collection of a style, like sources or layers mapbox-gl-style-spec#220
• Add map.setSprite(spriteUrl)method Add map.setSprite(spriteUrl)method #2058
• Add paint property for icon image URL Add paint property for icon image URL mapbox-gl-style-spec#485

[anandthakker]

Ah, I somehow missed #2058 in my search. In light of that one, I think it makes sense to rename this ticket to be only about Style#setGlyphs.