Dynamic overworld palette system

The most up to date code at time of writing can be found here. This also fixes some of the problems with the below system, like broken reflections and berry trees.

If you don't want to pull from a repository, you can look at this link here, and make the changes accordingly: https://github.com/pret/pokeemerald/commit/e4530a98cb1e4a572711563b1214468b26c3d688#diff-8306bd0c8ceabc2e2ba4ca90356ee24fadffe576b7a4b4caabe755c8f5d3f419