Fixing ImageAPI.getSplashArt() methods

[samDobsonDev]

When retrieving splash art images from DDragon, the version of the game is not needed, the image suffix is .jpg rather than .png, and the StaticChampion.getKey() field is used as a prefix to the skin number. To fix this issue:

Within ImageAPI I've added a new method buildSplashImageURL():

private String buildSplashImageURL(String file)
    {
        Realm  realm         = DDragonAPI.getInstance().getRealm();
        String cdn           = realm.getCDN();

        String preReplace = cdn + Constants.SEPARATOR  + "img/champion/splash" + Constants.SEPARATOR + file;
        return preReplace.replace(" ", "%20");
    }

I've then amended both the pre-existing getSplashArt() methods:

public String getSplashArt(String championKey, int skinNum)
{
        // http://ddragon.leagueoflegends.com/cdn/img/champion/splash/Aatrox_0.jpg
        return buildSplashImageURL(championKey + "_" + skinNum + ".jpg");
}

public String getSplashArt(String championKey, Skin skin)
{
        // http://ddragon.leagueoflegends.com/cdn/img/champion/splash/Aatrox_0.jpg
        return buildSplashImageURL(championKey + "_" + skin.getNum() + ".jpg");
}

This will now return the splash art for a given champion's skin in the correct format, e.g:

https://ddragon.leagueoflegends.com/cdn/img/champion/splash/Gnar_0.jpg

whereas before it was returning it in this format:

https://ddragon.leagueoflegends.com/cdn/13.11.1/img/champion/splash/150_0.png (where 150 is the champion ID)
or
https://ddragon.leagueoflegends.com/cdn/13.11.1/img/champion/splash/150000_0.png (where 150000 is the skin ID)