[#641] Fix viewport position with `fill` and `flex-width` scale methods when the followed target is on the right side of the map
[#641] Fix viewport position with `fill` and `flex-width` scale methods when the followed target is on the right side of the map

- Same fix used with `fill-height`.
- Maybe try not to duplicate this code?

MarkoIvanetic/melonJS,srbala/melonJS,rlugojr/melonJS,MarkoIvanetic/melonJS,gopalindians/melonJS,TukekeSoft/melonJS,gopalindians/melonJS,TukekeSoft/melonJS,gopalindians/melonJS,rlugojr/melonJS,srbala/melonJS,rlugojr/melonJS,srbala/melonJS,melonjs/melonJS,TukekeSoft/melonJS,melonjs/melonJS