Remove globally affecting call to Locale#setDefault

[BlvckBytes]

Greetings!

The call to Locale#setDefault within LocaleLoader#initialize threw me for quite the massive loop today, as it affected multiple other plugins which assumed Locale#getDefault to be the JVM's, and thus the system's locale, which mcMMO hard-coded to en_US.

While I have to admit that those other developers don't quite adhere to best practises by depending on this global state either, I still wholeheartedly believe that mcMMO should refrain from altering JVM-global-state nonetheless.

Also, since this initialization may occur after executing some of the static-blocks of other classes containing various formatters, many test-cases failed to execute due to formatting-discrepancies on my local machine, having had a non-english locale configured.

My proposal represents merely a quick patch, as to cut out altering global state, but the ideal solution would obviously be to use the locale as configured on the plugin; that would demand a few architectural changes, which I do not quite have the resources for, at this point in time.

I hope that this tiny but still rather significant issue can be settled soon.

Best Regards,
BlvckBytes

[nossr50]

Thank you for the write up and thorough explanation, and thank you for the PR as well.