Fixes for BW static sprites.
- Display gender differences whenever XY sprites would show them (TODO: show them whenever BW differentiated sprites are available).
- Fix pokemon being never shiny upon forme change (including megaevolution) unless the page is reloaded.
- Make Tools.getSpriteData more readable and partially support multi-gen sprites.
Merge pull request #189 from Slayer95/sprites

Fixes for BW static sprites.