Remove ACE submodule, just use the files.

This is the last submodule! Because of that, I could also remove the `.gitmodule` file. I removed an exclusion rule from our linter, tweaked the docs to not mention submodules, and updated the bundles. I noted the version (and commit) of ACE we were using, in case we want to upgrade or change it in the future.

As a bonus, we are now using the unminified version of the source. This could be a boon to debugging in the future, and we minify all our bundles anyways, so we don't lose anything.

r?