Revert "Add global overwriting option for extensions."

This reverts commit e6fe6de3fc0c2d03e2ed6945289d91ddcc9eac0b.
Finished capture_runas in ideal cases.

Plugins must use the provided CommandSender object in order for this to work, however. If they look up the player from the server via name, the proxied object will no longer be returned. This may be able to be fixed if play-dirty mode is active; the proxied CommandSender could be injected into the server's user table. Running as op currently doesn't work either, but that will be fixed in the future as well.
Don't naturally let extensions overwrite core functions and events.
Fix boilerplate test failure.
Fixed get_chunk_loc returning an invliad location (Whoops)
Merge pull request #222 from ACzChef/master

Fixed get_chunk_loc returning an invalid location (Whoops). Thanks ACzChef!
Experimentation with capture_runas to make it more resilient.
Merge origin/master

Conflicts:
	src/main/java/com/laytonsmith/core/functions/Meta.java
Added array_filter.
Added rclosure(){} and @nolinking, for future use in the Federated system.
Updated vim syntax highlighter to support double strings.
Procedure definitions shouldn't be restricted
Handle old style extensions properly in the error handler.
Merge origin/master
Catch exceptions in yml_decode, and create CREs.
Added cmdline_prompt_input event. Corrected an error in the compiler with smart strings.
colorize() was using the wrong optimization option.
Added syntax highlighting to http_request.
Handle non-existant ids in unbinds properly.
Added the undocumented async_player_chat event.